All posts by westtexordnance

Bartlein CFW Barrel Test

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Like many others in the precision rifle crowd, we were extremely excited to see Bartlein Barrels release their new Carbon Fiber Wrap (CFW) barrel blanks to market. Bartlein is an established heavyweight in the premium barrel market, holding numerous world records for accuracy across a wide range of shooting disciplines. They support competitive shooters in an incredible way; I cannot remember the last major PRS or NRL match I attended that did not have a Bartlein Barrel certificate on the prize table. They are currently the most requested blank manufacturer by our customers, and for good reason. They are well known to just flat out shoot. Our purpose in testing was to determine if the new carbon wrapped option would live up to the reputation established by the company’s excellent steel barrels.

First Impressions

The first thing we noticed on our test barrel blank was the amount of steel left on both the breech and muzzle end, compared to some of the other carbon barrel makers. Bartlein approaches barrel making from the perspective that accuracy and consistency are of utmost importance; weight savings are secondary. To that end, the breech end of their barrels features more steel to support the thread tenon in the action, and the chamber and throat during extended firing. The muzzle end also has a longer steel section, giving more support to muzzle threads for suppressor use. We are also told by Bartlein that the steel liner geometry under the carbon wrap is optimized for maximum support on both ends, with the knowledge that suppressor use is common and must be accounted for in the design of the barrel blank. This makes their carbon barrel blanks slightly heavier than that of competitors’ products, but the design features bear serious consideration if you plan to run your rifle hard.

24″ Bartlein CFW #13 contour finished barrel in 7mm bore size, 3.0lb total weight
Near identical barrel contour, #11 Medium Palma with shortened shank, in steel. This barrel is 23″ finished, so the weight savings with the CFW is in reality about 1lb 2oz.

Straightness and uniformity of the barrel was perfect. Bartlein marks all of their finished barrels with the final bore and groove dimensions on the breech end, and they exactly matched our results when gauging. The bore finish of our blank was impeccable, with no defects found on either lands or grooves. Once in the lathe and indicated true to bore, outside diameter concentricity to bore was within .002″. This has been a hallmark of Bartlein blanks for as long as we’ve used them, and it was great to see the same workmanship in the new design as well.

Bartlein is offering their carbon fiber blanks in four finish lengths (20″, 22″, 24″, and 26″), and three contours. Available contours are their #4 Bull Sporter, #13 Remington Varmint/Sendero, and the #14 M24/M40. The outside dimensions of all three contours are the same for the carbon barrels as for the steel which is helpful in figuring the exact amount of weight savings for each type, and especially helpful to builders and stock makers who already have established inletting programs for those contours. The company is maintaining a good selection of CFW blanks built and ready to ship, and you can find a list of available blanks here:

Bartlein CFW available in stock list

We chambered our test barrel with a Manson 7mm SAW II reamer, as this caliber was a perfect choice to test the barrel’s performance and compare data to test data from the many other builds chambered for the same cartridge. Our test barrel has a finished length of 24″, and a twist rate of 1 turn in 8.5 inches. We chose the #13 Remington Varmint/Sendero contour, and feel that this will be an extremely popular size with our customers.

Barrel Break in and Test Data

Barrel break in was completed with a Dead Air Armament Nomad-30 suppressor attached.

Break in load:

171 Barnes Match Burner HPBT

WTO 5x Brass, annealed

44.5grs H4350

CCI450

2.920” COAL

2.260”CBTO

2682/15.4 over first 10 shots through barrel. Break in roughly 1 MOA, with exception of one called flyer.

Barrel was cleaned after shot number 10, shots 11-15 fired were loaded as follows:

166 Hornady A-Tip, 2.225”BTO/2.950” OAL, 44.5gr H4350, CCI450, 5x Brass, produced 2708FPS/8.5SD, .225” bughole group

.225″ group fired at 100 yards using Hornady 166gr A-Tips and 44.5grs H4350.

Shots 16-23

162ELD-M, 2.945”OAL/2.255”BTO, 44.5 H4350, CCI450, 5x Brass

2718FPS/10.8

Shot in approaching thunderstorm, wind high and switching from all directions

Group 1: .769”

Group 2: .869” 5 shot

Cold Bore Shift Test, shots 24-29

Same load data as above, 1 shot fired from completely cold barrel and suppressor, followed immediately with 2nd shot. Repeated 3 times. Worst 2nd round deviation was .426” from cold bore shot. The others were not measurable, as the shots were touching and subsequent shots had made exact measurements impossible.

Muzzle device testing

Same load data as above. Wind 13-15 and gusty.

Bare muzzle

2711/2.2, .8” group.

Dead Air Nomad 30 Suppressor/E-Brake

2718/10.8, .5” group. Less than .5MOA POI shift, at 8:00 position from bare muzzle.

Hawkins Tank ST Muzzle Brake

2704/4.5, .7” group. POI is 1.7” high from bare muzzle.

Heat stress test

Rifle configured with Tank-ST brake for heat test. Same test load as used for muzzle device testing. Three consecutive 3 shot groups were fired, allowing the barrel to cool 2 minutes in between shots to determine accuracy baseline. Wind during groups was 13-18MPH gusty full value.

Group 1: .790”

Group 2: .383”

Group 3: .862”

Average group size: .678”

2704/5.2 across all shots fired

Rapid fire test, 10 rounds fired as fast as target could be reacquired. Ambient temp was 81 degrees.

First three shots went in .370”. Total group size was .966”

2712/9.0SD over all shots fired

10 shot, rapid fire group at 100 yards.

Conclusions

The Bartlein CFW blanks are exactly as promised, producing accuracy that is every bit equivalent to their well know steel barrels but with less weight. Of note is the observed POI shift from bare muzzle to suppressor, which was negligible. The barrel reacted as expected to the heat stress testing, remaining true to the original point of impact throughout the shot string. Accuracy did degrade with speed shooting, but remained sub-MOA and produced the most accurate heat stress group of the three carbon fiber blanks tested. Cold Bore shift was statistically non-existent in this barrel, which is of extreme importance especially for a long range hunting rifle.

If you are considering what barrel blank to use for your next build, the Bartlein CFW’s deserve serious consideration. When used as part of a properly built rifle they can be counted on to shoot lights out, every time.

Paradigm Carbon Barrel Test

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Paradigm Carbon is a fairly new contender in the ultralight rifle barrel market. They are not new to carbon fiber, having developed methods for it across other industries for quite some time. One of their sales reps reached out to us regarding their barrels, and we ordered a 7mm blank to test out. After all, half the fun of building custom rifles is testing out new technology as it evolves!

First Impressions

The Paradigm barrel blank has some design features that are different from other carbon barrel makers. The obvious first difference is the lack of any steel capping the carbon fiber on the muzzle end! Due to their wrapping process, the company states that the extra steel material there is not required. This of course means that on most bore sizes, 5/8-24 TPI muzzle threads are out of the question. The steel barrel liner is large enough to thread 1/2-28TPI, and Paradigm supplies a 1/2-28 to 5/8-24 thread adapter for common muzzle device use. An advantage to this wrapping method is that according the Paradigm, their barrel blanks can be cut to any desired finish length, rather than being limited to a pre-determined length. This could be very helpful for rifle builders, as it cuts down on the number of different blanks needed in stock to maintain inventory.

At 2 lbs 6 ounces, this Paradigm Carbon barrel is the lightest 26″ barrel we’ve built to date.

The steel portion of the barrel blank is produced by Rock Creek barrels, and is rifled using the button cutting method. Our initial borescope inspection showed the bore finish to be average. Slight tool marks from the rifling button were still visible, but not in a serious enough condition to cause concerns about excess fouling or accuracy problems. There were no major defects in the bore, and overall straightness and concentricity of the bore to OD was very good. Paradigm offers two contours; the 88 and the 95, whose names correspond to each contour’s muzzle diameter. You can find a print with dimensions for each contour here. We went with 95 contour for our test barrel.

Machining the barrel blank was uneventful, just the way we like it! The blank indicated easily, and it was quickly possible to achieve TIR of less than .0005” on an SSG range rod. We chambered this blank with our Manson 7mm SAW II reamer, as this caliber was a perfect choice to test the barrel’s performance. We have mountains of test data from other builds in this caliber, so it makes a great established baseline. The carbon fiber on the muzzle end machined well, and showed no signs of de-lamination.

Barrel Break in and Test Data

Break-in load: 171 Barnes Match Burner, 2.920″COAL, WTO 5x fired brass, 44.8grs H4350, CCI450

2729/13.7SD. Break in shots went into 1 MOA, except two flyers that went 2” left of group. One was a clean shot and one was fouled. All trigger pulls felt good. Cleaning during break in was normal, with excess copper fouling build up. Copper failing began to diminish after shot number 6.

166 Hornady A-Tip, 2.235”BTO/2.960”OAL, 44.5gr H4350, CCI450

2745/22es over 3rds, 2741/11.2SD over 9.

.228” bughole

No cold bore shift observed, either shot to shot between cold shots or on successive warm shots afterward.

.228″ group fired using the Hornady 166gr A-tip, 44.5grs H4350, CCI450 primer, and WTO 7mm SAW brass

Group testing with various muzzle devices

Test load: 162ELD-M, 2.945”OAL/2.255”BTO, 44.5 H4350, CCI450, 5x Brass

Bare Muzzle

2736/11.5SD, .529” group

Dead Air Nomad-30 Silencer w/e-brake

2754/7.0SD, 475” group

POI shift from bare muzzle is 1.4” straight down.

Hawkins Tank-ST Muzzle Brake

2738/9.6SD, .799” group(wind change and gusty), next group in better conditions was .274”

POI shift from bare muzzle is .25” straight down

Heat stress test

10 shot group from heat stress test. The first shot fired is the hole .7″ directly above center of target. Total group size is 1.012″, roughly .97 MOA.

Rifle configured with Tank-ST brake for heat test. Same test load as used for muzzle device testing. Three consecutive 3 shot groups were fired, allowing the barrel to cool 2 minutes in between shots to determine accuracy baseline.

Group 1: .799”

Group 2: .275”

Group 3: .782”

Average MV across all groups was 2748/10.4 SD

Average group size: .619”

Rapid fire test, 10 rounds fired as fast as target could be reacquired. Ambient temp was 101 degrees.

First three shots went into .480” group. Group size increased with barrel heat, but POI did not shift. Total group size for 10 shot string was 1.012”. Muzzle velocity for entire string was 2744/8.5SD.

Conclusions and Final Thoughts

I have to admit that I was skeptical of this barrel when we received the first blanks. The lack of steel on the muzzle end didn’t look right to me, and I had doubts that its performance would live up to the company’s claims. After testing though, I’m very impressed with it. The accuracy potential of this barrel blank is as good as any of the others on the market, assuming its properly chambered and mated to a properly built rifle in all other areas.

The barrel’s performance under heat stress was very good, considering it’s intended use. For high volume shooting such as PRS and NRL competitions, I’d still recommend a heavy contour steel blank for maximum performance. However, our test barrel proved absolutely trustworthy for its intended purpose, and showed itself more than capable of standing up to abuse when needed.

One concern that remains for me is muzzle wear when used with a suppressor. Because of the limitation of 1/2-28TPI muzzle threads, the decreased amount of wall thickness around the bore at the muzzle end could lead to premature muzzle wear, especially on large magnum calibers. We saw no issues with it during this test, but given that less than 100 round were fired I did not expect to. This will be a concern to be re-visited over time, as the barrel continues to wear. Of course, this is a non-issue for the shooter who is not planning to run a suppressor for extended strings of fire.

Our test is too preliminary to make any judgments about barrel life. The barrel does quickly dissipate heat through the carbon and cooled down relatively quickly, especially given that all of our testing occurred at ambient temperatures between 90 and 101 degrees! The barrel has approximately 60 rounds on it at completion of our test, but has yet to show signs of any kind of speed up. We inspected the throat with a borescope after testing, and saw no signs of premature erosion.

In summary, our opinion is that Paradigm barrel blank is an excellent option for reducing overall rifle weight, without sacrificing accuracy. We will be stocking these blanks in certain configurations, and look forward to building more into our rifles in the future!

Testing the 166 A-Tip in the 7mm SAW

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Measurements and test rifle data

Bullet OAL: 1.503”
Base to Ogive, measured on Forster Datum Dial tool: 0.778”
Ogive to nose: .725”

Test Rifle
Bighorn Arms TL-3 SA #1717, Kahles K525i SKMR3, 28″ Broughton 8.5″ twist 5C rifled barrel. This barrel was chambered with our 7mm SAW II reamer, and at time of testing has had approximately 350 rounds fired since new.


Max seating depth measurements


Cartridge OAL: 2.988”

Cartridge BTO: 2.263″

Given that the maximum OAL/BTO falls slightly outside of magazine length(2.965″ max in our MDT non-binder plate mags), we opted to begin our loading .030″ off the lands. We chose to use H4350 powder for our initial work up, as it has proven very accurate with all bullets tested in this cartridge from 160 up to 185 grains. A go-to match load for the 160gr Sierra Tipped MatchKing has been 46.6gr H4350 across multiple 7mm SAW barrels, so we began slightly below that in hopes of finding a similarly good node without much trouble. We started at 45.6gr, and decided to also test down to 45.3 as well once we saw that our starting load was already producing velocity above 2800 FPS.

100 yard beginning OCW test groups, 45.3-46.2gr H4350

Our original intent was to do a standard 100 yard OCW test, with 5 shot total groups fired in a round robin sequence. However, after getting through three rounds per charge weight and seeing all four charges test produce sub .5MOA groups, we decided to move out to 500 yards and begin looking for vertical dispersion.

Here is the velocity data for each charge weight tested:

All loads on 3x fired WTO/Alpha Munitions 7mm SAW brass
2.233”BTO, CCI450 Primer
45.3: 2836/4.3SD, .210” group. 2823/7.8 when shot on brand new brass
45.6: 2842/10.4SD, 442” group
45.9: 2865/6.9, .510” group. Possible flyer induced by heavy mirage. Shot 2852/8.6SD on brand new brass.
46.2: 2879/5.9SD, .411” group, established max for this barrel. Bolt lift easy, primer looks fine, but click at top of bolt lift stroke. Slight ejector cutout mark on case head.

Since the 46.2gr charge was borderlining max pressure in our test rifle, we fired round robin sequence groups at 500 yards with 45.3, 45.6, and 45.9. Both 45.3 and 45.9 produced less than 2″ of vertical dispersion, with 45.9 producing less than 1″ of vertical. If not for a blown wind call, 45.9 would have produced a fantastic group measuring just under 1.5″ total. Wind on test day was moving at 13-18MPH full value, with some very significant mirage also to contend with. We opted to cease testing for the day so as not to build skewed results based on conditions.

The next morning, we shot the 45.3 and 45.9 grain charge weights at 850 yards, with no load producing a clear advantage. Both loads showed very little vertical dispersion, and Hornady’s published BC of .332 matched up well. The farthest distance available on the test range is 1090 yards, and here the 45.9 grain charge showed itself as the true winner.

1090 yard group, just under 4.5″ total

A sub .4 MOA group at almost 1100 yards is a keeper from any rifle and load combination. This was in line with previous accuracy benchmarks set for the cartridge and other bullets, and once again the Doppler tested .332 G7 BC worked out to an accurate firing solution with no additional tweaking.

Final Observations and thoughts

1. In our opinion, the Hornady 166gr A-tip is exactly what it claims to be. It is a highly accurate, premium consistency level projectile for producing utmost uniformity in precision rifle shooting. The bullet’s weight and BC combination are as close to ideal as is currently available for a mid-capacity, do-all cartridge like the 7mm SAW.

2. More testing is needed to confirm this, but in this trial the A-Tip did not appear to be sensitive to seating depth. The Redding micrometer seating stem in our Type S 7mm SAW die set seated the bullet perfectly, and did not effect the tip of the projectile.

3. The bullet produced very similar velocities to the 162gr ELD-M, which would lend itself well to possibly using the ELD-M as a short range practice/club match bullet, and the A-Tip as a more intense competition projectile.


25 SAW Cartridge Development

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An Idea is Born

            Several years back, Miles Johnson and I met at Precision Rifle Series match in Navasota, Texas. The 7mm SAW was still in its early stages, and that Lone Survivor Foundation fundraiser was actually the first 2 day match I had shot the cartridge in. I shot well for my skill level at the time, and the 7mm SAW performed exactly as intended. Since then, it has grown to become a very popular chambering for our shop and many others. At the same time, Miles was working on a prototype .25 caliber bullet for competition that would take advantage of a ballistic sweet spot. He designed a bullet that retained the high BC abilities of the 6.5mm family (and actually exceeds many 6.5mm designs), while producing less recoil due to the bullet’s lighter weight because of the smaller .257 bore diameter. This hit the market as the Blackjack Bullets 131gr ACE projectile, to say it has made a splash would be an understatement. Blackjack currently offers not only the ACE projectile, but also a large selection of fast twist barrel blanks and chamber reamers for a myriad of different .25 caliber wildcat cartridges to take advantage of their bullet’s performance.

            We were, like many others in the precision rifle world, very excited to test out the capabilities of the ACE projectile. Given that our factory 7mm SAW brass came into full production this year, the timing was now perfect for one wildcat to give birth to another. We ordered up a pile of bullets, and with some sound advice from the Blackjack crew set designing a reamer for the .25 SAW. Dave Manson delivered the new reamer ahead of schedule, and before long we were off to shooting!

The Test Rifle

            The test rifle for the new cartridge is one of our new standard builds, called the Red River package. This build package is purposely designed for serious match shooting, and makes use of components designed and built by some of the most highly skilled precision rifle competitors in the sport.

WTO Red River Build Package

Chamber Notes

            All testing was done using the prototype reamer, which was designed with a .292” Neck diameter of a .112” Freebore length. The neck yields a clearance of .002” per side on our 7mm SAW brass without neck turning.

We developed the following measurements for seating depth and cartridge length using the Wheeler seating depth method (learn more here), a Mitutoyo 6” digital caliber, and a Forster Datum Dial measurement tool:


Bullet Measurements


OAL: 1.436” -.005”
BTO: 0.749”
OTN: .687”

Unfired chamber measurements
Test bullet: 1.432”OAL/.746”BTO
Max COAL: 2.935”
Max BTO: 2.249”

A few other .257 cal bullets were measured, and the results are below for those interested:

110 Accubond: 2.250” BTO/2.760” OAL, bearing surface right at neck/shoulder
115 Berger Hunting VLD: 2.250” BTO/2.835” OAL, bearing surface well above neck/shoulder. Optimum seated.
110 Hornady ELD-X: 2.250” BTO/2.808” OAL, optimum seated.

Load Development



Break in load: 41.5gr RL16, CCI450, 2.230”BTO. Brass sized by one pass through 6.5CM die/.289” bushing, then final pass in Whidden 7mm SAW die with .281 bushing and .250 expander.
2893/13.4SD, .5” at conclusion of break in. Easy bolt lift and primer looks fine, but shows ejector mark on case head.
Same data as above but 42.0grs H4350: 2888/6.0, .55” group, easy lift, same case marks

Reloder 26 powder test, one shot per charge weight
2.229” BTO, CCI450, new formed brass as above.
44.0: 2800FPS, very mild start load
45.0: 2870FPS
45.5: 2904FPS
46.0: 2947FPS
46.5: 2990FPS
47.0: 3034, easy lift, no signs on Case head, primer beginning to flatten but not crater
47.5: 3074, easy lift, flowback on primer indent, max Case capacity. Established max for this powder

100 yard OCW test
46.4: 2984/19
46.8: 3027/14
47.1: 3038/33
All three charges shot the first three shots in sub .4”, then the fourth shot of every charge weight was a wide flyer. 33 rounds down, cleaned before continuing test

46.4: 2 foulers Fired on clean barrel, then 3 shots for group. .131” group, 2980/4.6SD for 3 shots. Combined numbers from OCW makes 2982/8.6 over 7 shots
Loaded the 46.4 load on 1x Brass, sized to 1.625” at .375 datum. Whidden sizer with .250” expander produced 2994FPS, equivalent accuracy.
Hornady die with .281 bushing and no expander produced 2981FPS, higher SD but same accuracy.

Additional Powder Testing

The following charge weights were formulated based on a predicted 52000 PSI chamber pressure. As powders and actual pressures can vary significantly from predictions, we loaded the predicted charge weights and recorded the actual results we found. The charge weight and predicted velocity for each are listed, followed by the actual fired data and group size if a group was fired.

  • Reloder 23: 45.7/2861, 3018 actual, max pressure, 1 shot only.
  • Reloder 16: 40.8/2849, 2866/3.7SD actual, .6”, safe pressure.
  • IMR7828SSC: 46.0/2874, 2951/8.4SD actual. .35”, max pressure. Slight heavy lift at top of stroke
  • H1000: 48.9(110% predicted Case fill)/2845, shot 47.5, 2927/4.0SD, .5”, max fill
  • H4350: 41.6/2767, 2879/5.1 actual. .75”, safe pressure but near max.

Field testing and BC confirmation

            With an established accurate load running 46.4 grains of Reloder 26, it was time to move out to longer distances and start putting lead on steel. Blackjack recommends a .330 G7 BC for the 131 ACE, so we used that as our start point. The test barrel now had 80 rounds on it which was enough to check for a speed up, so before shooting at distance we re-checked velocity on the load. As expected, a slight velocity increase had occurred. The 46.4 grain load was now running just a touch over 3000FPS, and still shooting a bughole at 100 yards. Our first plate was 400 yards, and the projected trajectory would require 1.6 mils of elevation. At this distance the bullet shot slightly flatter than predicted, only requiring 1.5 mils for a center hit. The first 400 yard group came in under 2”(less than .5MOA at that distance), so we were comfident in the load to go further out. At 600 yards, the actual drop lined perfectly with the prediction on 3.0 mils. With a slightly switching wind in effect we printed a 3 ¾” group at 600, with only 2.5” of vertical dispersion. The group size didn’t set any records, but from experience this level of accuracy is more than adequate for a competition or long-range hunting rifle. Based on the solid data gathered, we moved on to 1090 yards. I have a 1 MOA round plate and a 2 MOA square at this distance, so I decided to burn the first shot on the 1 MOA plate. If I hit it on the first round I’d have my self-esteem boost for the day, and if not the area around the plate would give me excellent feedback for a correction. I dialed the predicted 7.6 mils of elevation and sent the bullet through warm west Texas air. It sailed just left of the target, and from the dirt impact it appeared to have been just slightly high of my aiming point. Armed now with humility and a good wind call, I dialed down a tenth and moved to the 2 MOA square. The first shot on the plate touched my center aiming point! I ran the bolt and dropped another one into the orange paint, seemingly on top of the first impact. A third shot made a nice group, falling just slightly slow of the first two hits. The group measured at 4 ¾”, roughly .41 MOA at that distance. After adjusting the BC numbers based on the data, we found a .335 G7 to match almost perfectly. 

1090 yard group, 25 SAW with 131 gr Blackjack ACE. 4.75″ center to center

            There were still a few loaded rounds left, so I decided to throw on a Dead Air Armament Nomad-30 suppressor to get a feel for the cartridge’s recoil impulse in field shooting. I’ve been running that suppressor and my 6.5 Creedmoor trainer barrel on my personal match gun, so this would give me a good impression of felt recoil versus another popular cartridge. I checked for POI shift at 100(there was none), and then got on my 1 MOA plate at 400 yards. Armed with the knowledge that 1.5 mils would hit it there and a nice constant breeze, I made an easy first round hit on the small steel. The succeeding shots just made the impact of the first bullet darker, so I knew it must be a decent group. After inspecting the plate, I found that it was my personal best group to date at that distance. Those three shots measured just under 11/16” center to center, roughly .65”. That works out to .16 MOA!

Summary and Lessons Learned

  1. This cartridge/bullet combination is crazy accurate! We’ve always loved how consistent the 7mm SAW is, and the 25 SAW is more of the same. It didn’t require a bunch of tuning on seating depth or loading gymnastics. Load it .020” off the lands, give it the powder it likes, and get to shooting tiny groups.
  2. Future reamers will probably run a slightly longer freebore. The .112” Freebore put the bullet around 2.935” max OAL, and the extended MDT or A/W magazines can accommodate 2.960” with ease. We will probably end up lengthening the freebore to .142”, so that a loaded round .020” off lands is at 2.945”. This would still mag feed very well, but give just a shade more case volume (and maybe a little extra speed)
  3. We will probably have Redding make 25 SAW custom FL sizer dies. We think this would be the most straightforward case forming method, and save time over a two-step process using different size neck bushings.
  4. The 7mm seating stems in our Whidden, Redding, and Hornady 7mm SAW die sets all reliably seated the 131 ACE without issue. The Redding stem left a slight contact ring, but did not cut the jacket or contact the bullet nose.

7mm SAW 185 Nosler RDF Test Data

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The Nosler 185gr RDF bullet is a fairly recent entry into the long range 7mm projectile arena, and one that deserves consideration. Given the case capacity and previous experience with the 7mm SAW, we feel like the RDF is the upper limit of the balance between speed and bullet weight for this cartridge in a magazine fed rifle. Nosler was kind enough to supply us a few boxes of the new RDF for testing, and we’re happy to provide the results below.

Test Rifle: Bighorn TL-3SA #1717, 26” Bartlein MTU contour barrel, 1-8.5” twist rate, 5R rifling profile
This is Clayton’s current PRS barrel, and has shown to be consistently accurate. In our experience, this barrel runs in the middle of the pack with regard to muzzle velocity in this cartridge, so it acts as a good test subject that doesn’t skew results up or down. There were approximately 900 rounds through the barrel at test time, and around 250 rounds fired since it was last cleaned.

Max COAL in new SAW II chamber: 2.947”. This equates to 2.259″ cartridge base to ogive when measured on a Forster Datum Dial tool.

The test barrel shows approximately .020″ of throat wear since new, so the decision was made to begin testing 2.950″ COAL for simplicity. On test day we had a variable full value right to left wind, ranging from 7-15 MPH. Minimal consideration was given during firing to wind speed; our main focus was to establish a charge weight with minimal vertical dispersion.

Brass: WTO/Alpha Munitions 7SAW
Primer: CCI BR-4
Powder: H4350 lot 5814
All loads 2.262”BTO/2.950” OAL


Charge weight/velocity, 200 yard range
44.0: 2577/8.5Sd, .856”vertical over 5 shots
45.0: 2638/7.0, .819” vertical over 5 shots.
45.4: 2660/11.0, .88” vertical over 5 shots
45.8: 2661/7.2, .604”vertical over 5 shots. Most accurate of all charges, .712” total group
46.2: 2682/12.0, .872” vertical over 5 shots
46.6: 2701/9.2, 1.138” vertical over 10 shots. Slight resistance at top of bolt lift on 3 rounds, established max for this barrel

200 yard 5 shot group during ladder testing with H4350 and Nosler 185 RDF

Field data
255 degree Direction of fire/65 degrees/60%RH/27.15Hg station pressure(approx. 2700′ ASL)
Test load for field firing was 45.8gr H4350, 2661FPS Average muzzle velocity.

200: 0
840: 6.3 Mil, 1” vertical dispersion
1070: 9.35 Mil
Notes: Nosler publishes a .357 G7 BC for this bullet, which was used to calculate initial firing solutions. The published BC lined up relatively well with the field data produced, although a custom drag model would be even better. At 840 yards, the bullet consistently shot .1 mil flatter than predicted. At 1070, it required .05-.1mil additional elevation versus predicted.

100 yard seating depth test(3 shots per string)
2.272”: 2674/6.3, .452” group
2.262”: 2678/4.0, .593” group
2.242”: 2661/12.5, .487” group

This seating depth test was not exhaustive, but rather intended to determine whether or not this bullet would show major signs of seating depth sensitivity. We found the 185 RDF to be tolerant rather than volatile, and were very pleased with it’s overall performance.

WTO 7MM SAW FACTORY BRASS TESTING AND LOAD DATA

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  The first run of factory 7mm SAW brass is in final QC this week and getting ready to ship! With delivery inbound, we thought this would be a good time to post some of our test data on this brass. This data was compiled using the final pre-production case batch, and based on the data gathered we gave the green light to Alpha Munitions to go forward with full production. From the very beginning of this project through the final product the team at Alpha Munitions has provided invaluable insight, professional service, and unbeatable quality. On personal level, this has been extremely fulfilling to watch this concept go from a thought to a mainstream cartridge!

 This test was performed using my personal competition rifle built on a Bighorn Arms TL-3 LBRP action, and running a 26″ Bartlein 1-8.5″ twist 5R rifled MTU contour barrel. This barrel has the 7mm SAW II chamber, and runs from AI A/w magazines.  This gun also runs our own WTO Mk2 muzzle brake.

Case weight: 171.1 grains, Standard Deviation 0.2 grains. Sample size was 20 cases, all randomly selected from a box of 100 pieces as received. Neck wall thickness measured .0146″.

Load 1: 162gr Hornady ELD-M, 41.8gr Hodgdon Varget, CCI BR-4 Primer, 2.250″ base to ogive length. 2809FPS average, 8.7FPS SD over 12 shot test

Load 2: 150gr Hornady ELD-X, 42.5gr Hodgdon Varget, CCI BR-4 Primer, 2.230″ base to ogive length. 2939FPS average, 18.1FPS SD over 4 shot test

Load 3: 162gr Hornady ELD-M, 42.5gr Hodgdon Varget, CCI BR-4 primer, 2.250″ base to ogive length, 2854FPS average, 8.1FPS SD over 5 shot test

Load 4: 185gr Nosler RDF, 44.5gr Alliant Reloder 16, CCI BR-4 Primer, 2.250″ base to ogive length, 2674FPS average, 27FPS extreme spread. 3 shots only in test

Load 5: 185gr Nosler RDF, 45.0gr Alliant Reloder 16, CCI BR-4 Primer, 2.250″ base to ogive length, 2683FPS average, 5.3FPS SD over 6 shot test

Load 6: 162gr Hornady ELD-M, 46.2gr Alliant Reloder 16, CCI BR-4 primer, 2.245″ base to ogive length, 2878FPS average, 9.0FPS SD over 6 shot test

Load 7: 160gr Sierra TMK, 41.8gr Hodgdon Varget, CCI BR-4 primer, 2.281″ base to ogive length, 2813FPS average, 24FPS extreme spread over 4 shot test

  In this initial testing, all of the loads listed above produced 100 yard accuracy of .5MOA or better. All of these loads also showed no evidence of excessive pressure in the test rifle, although the heavier charge weights are approaching maximum for this barrel. After further waterline testing at 200 and 600 yards, I selected Load 7 with the 160gr Sierra Tipped MatchKing as my competition load for this barrel. The muzzle velocity average has increased slightly to 2820FPS as this barrel has settled in, and has stayed extremely consistent. This load was used to take my first Top Ten finish in a national level match last month at the Rifles Only Brawl, and will continue to be my go-to load on this rifle for everything but ELR matches.

WARNING: ALTHOUGH THESE LOADS WERE  VERIFIED SAFE IN THE TEST RIFLE, ALWAYS START LOW AND WORK UP IN YOUR OWN RIFLE! THERE ARE MANY VARIATIONS IN BORE/GROOVE SIZE, POWDER LOTS, BARREL LENGTH, AND OTHER FACTORS THAT CAN EFFECT CHAMBER PRESSURES. 

 

Alpha Munitions brass for the 7mm SAW

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  A couple of months ago, we built a 7mm SAW for one of our long time customers, and he sent us some Alpha Munitions .308 Winchester Small Rifle Primer brass to use for load development in his rifle. It was extremely consistent stuff and worked very well for his build, so I decided to run some in my personal 7mm SAW as well and let y’all know the test results.

If you’ve read other information we’ve put out about this cartridge, you know that we designed it around the Lapua .308 Palma Case. In comparing the Alpha .308 SR brass to the Lapua, the two lots we have tested are every bit as consistent on weight as the Lapua offering. The Alpha brass does have slightly less internal volume; my test lot averaged 53.4 grains of water versus 54.6 grains of water for the Lapua Palma. Also of note is the Alpha primer pockets. They are just slightly tighter than new Lapua pockets, which should help with even greater brass life. If you are using an adjustable jaw priming tool such as the Forster, you’ll want to ensure that the priming tool’s alignment to the pocket is perfect to avoid damaging a primer during seating. 

To form the cases to 7mm SAW dimensions, I used our custom Whidden Gunworks die set and a 2 step form process that has proven to work very well for me. First, I debur the inside and outside of all the necks, put a sparing amount of One Shot sizing lube on the cases, and then run all the cases through the Whidden sizing die, with a .325″ Neck bushing installed and the expander removed. For the second step, I install a .312″ neck bushing in the die and re-install the expander ball positioned as high in the die as it will go without interfering with the bushing. This keeps the case mostly supported by the die as the expander passes through the neck on the return stroke. I then run the cases through the .312″ bushing, which puts the neck to it’s final dimension. This method yields formed cases with very little runout, which are ready to load and as the test data below indicates are more than capable or producing match ready accuracy on the first firing. 

I’ve been building a load for my rifle to complete at the upcoming Precision Rifle Series match at Q Creek Ranch in Wyoming, and settled on the 180gr Sierra MatchKing bullet and Alliant’s new Reloder 16 powder. With my existing Lapua Brass, 44.5 grains of RL16 produced muzzle velocity of 2700 FPS and extremely consistent accuracy at all ranges. Here are the specs of my rifle:

  • Bighorn Arms TL3 LBRP short action
  • Bartlein 1-8.5″ #23 contour barrel, 26″ length
  • McMillan A5 stock
  • WTO Mk2 brake
  • WTO short action bottom metal with A/W mags
  • Huber Concepts 2 stage trigger
  • Kahles K624i with SKMR3 reticle
  • Hawkins Precision Heavy Tactical rings

This barrel currently has a little over 2000 rounds on it, and has shown no velocity change since initial break in. Based on the load already developed on Lapua Brass, I decided to run a test on the Alpha .308 SR brass to see if equivalent accuracy and velocities were achievable. Taking into consideration the reduced internal volume, I shot a modified ladder test with Reloder 16 to determine maximum pressure.

180 SMK, 2.950″ OAL, CCI #41 primer, Reloder 16

  • 43.0 grains: 2651FPS, no pressure
  • 43.5 grains: 2690FPS/15ES, no pressure. .7″ group at 200 yards
  • 43.8 grains: 2702FPS/5ES, slight ejector mark on case head, easy bolt lift. 1″ vertical group at 200. Established as max charge for this brass/bullet/barrel. 

  With a good load found at 43.5 grains of RL16, I loaded a few more and decided to do some longer distance testing. I had several customer’s rifles to collect field data on the following morning, so once done with them I pulled my rifle out and shot two 600 yard groups. Conditions were 75 degrees, with a 12-15MPH full value wind from left to right. The first is the group pictured at the top of this post. The highest shot was the cold bore, followed by the two stacked together slightly below. Total group size measured 3.2″ center. I followed this group with a second group at 600 yards using my established load on Lapua brass. The second group was shot on a warm barrel, and measured 3.4″ center to center. 

 Later that evening, I pushed both loads out to 1055 yards. With very similar conditions to the morning shoot, both produced 5 shot groups hovering right around 6 inches, which I was more than pleased with. Of note in the 1055 yard groups was that the Alpha brass load seemed to steer better in the wind. While both loads exhibited about the same vertical dispersion, the Alpha brass load all fell within about 2.5″ horizontal dispersion. This may simply have been caused by more consistent winds or better calls during that string of fire and have nothing to do with the brass itself, but I plan to continue side by side testing to see if this is an actual trend. 

  In summary, our testing showed the Alpha Munitions .308 Winchester SR brass to be a very high quality and useful alternative to Lapua brass for 7mm SAW shooters. This test also answered a relatively frequent question on this cartridge of “can you really get match grade accuracy on the first brass firing?” Unequivocally, yes you can!

 

SwitchLug Compatible Action List

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 SwitchLug Compatible Action List

      This list is broken into two categories; direct fit and retrofit capable actions. Direct fit actions have the correct index pin locations for the SwitchLug to be a drop in fit. You will still need to have a barrel properly machined and headspaced for the SwitchLug interface, i.e. an existing barrel cut for a standard .187” or .250” recoil lug will not work in its current state. Retrofit capable actions will not accept the SwitchLug without action medication, but are suitable for modification to function correctly with the system.

          We will continually update the Compatible Action List as information is received. If you have an action that is not listed and are wondering whether it can be fitted with the SwitchLug, please feel free to contact us. General requirements for compatibility are that the action must use a barrel thread tenon that is less than 1.0625” OD, and must have a flat action face i.e. the barrel does not fit into a recess with an integral scope rail or recoil lug that protrudes forward of the barrel mating surface.

 

DIRECT FIT ACTIONS

·       WTO Claymore, all lengths and calibers(does not fit XL action)

·       WTO Claymore HD, all lengths and calibers

·       Stiller Predator, short, medium or long

·       Stiller TAC 30

·       Stiller TAC 300

·       Stiller Spectre, short or long

 

 

RETROFIT CAPABLE ACTIONS

·       Remington 700, short or long

·       Surgeon 591

·       Surgeon 1086

·       Bighorn Arms TL and SR series

·       Lone Peak Razor

·       Lone Peak Fusion

·       Defiance Rebel Old style(pinned recoil lug)

·       Defiance Deviant

·       Defiance Rebel New style(integral lug)

·       Badger M2013

·       Borden Alpine

·       Borden Timberline

·       Kelbly Atlas

7mm SAW barrel length and power tests

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As part of the development of the 7mm SAW cartridge, we tested several different powders for suitability. We also started the test barrel at a length of 31 inches, and performed a cut-down test to determine the amount of velocity loss that could be expected with various barrel lengths. The test barrel is a Krieger 5R stainless 1-8.5″ twist, .277″bore/.284″ groove.  All loads shown were tested using formed Lapua .308 Palma brass. Hopefully you find this information helpful as you gather data for your next rifle!

Maximum overall lengths for various bullets

Short throat, .045″ Freebore. This chamber would be necessary for shooters using standard AICS .308 magazines,  Magpul AICS pattern PMAGS, the HS Precision DBM system, or standard length internal magazine boxes). These overall lengths were measured after barrel break in as well. In an unfired chamber, the lengths would be approximately .005″-.010″ shorter than listed.

162 Hornady ELD-M: 2.850”
180 Berger Hybrid: 2.915”
168 Berger Hunting VLD: 2.840”/1.414” measured bullet length
183 Sierra Match King: 2.988”/1.603  measured bullet length
171 Barnes Match Burner: 2.835”/1.410 measured bullet length

Long throat, .150″ freebore. This chamber is recommended for running the 162 ELD or 168 Berger VLD in the AI A/W magazine, Alpha Mags, Accurate Mags without binder plate, and 3.000″ internal magazine boxes.

183 SMK: 3.090”
180 Hybrid:  3.020”
162 ELD: 2.955”
168 Berger VLD: 2.945”

All four listed bullets would seat with bearing surface above the neck/shoulder junction in this throat length.

Powder Test, Hodgdon Varget

Break in Load
162 ELD-M, 2.830”OAL
39.0grs Varget
Fed 205M
2733FPS/11.5SD
.5” at 100 yards, all sub MOA during break in

162 ELD-M, 2.840 OAL, Federal 205M Primer

40.0: 2806FPS
40.5: 2832FPS
41.0: 2852FPS
41.5: 2886FPS
42.0: 2879fps
42.5: 2889FPS
43.0: 2913FPS
43.5: 2937fps
44.0: 2989FPS, MAX PRESSURE. Bolt lift still easy, but substantial primer flow back and small eject swipe.

 

Powder Test, IMR 4451

162ELD-M, 2.840”OAL, Fed 205M primer

45.5:  2865FPS
46.0:  2859FPS
46.5:  2908FPS easy extraction, but max case fill at this throat length

IMR 4955 powder
162 ELD-M, 2.850”
Fed 205M Primer

46.0: 2827/27ES, 2.5” vertical at 200

IMR7828SSC powder
162 ELD-M, 2.850”
Fed 205M Primer

46.0: 2725/26ES, 3” vertical at 200

H4350 powder
162 ELD-M 2.850”OAL
Fed 205 M primer
45.5: 2878/20ES, 1.5” vertical at 200
46.0: 2901FPS
46.5: 2924FPS
47.0: 2951FPS
47.4: 2948FPS
All shots from 46.0 to 47.4 were within .5MOA vertical at 200
Re-shot 47.0 at 100 yards, sub .5 MOA accuracy, 2933FPS/38ES

 
183gr Sierra MatchKing/H4350 powder, 2.978” OAL

44.5: 2670FPS
45.0: 2694FPS, primer looks great
46.0: 2751FPS, primer looks the same at 45.0
46.7: 2782FPS, max load, compression causes issues seating to 2.180”

 

All loads after this point were tested on chamber with .150” Freebore.

183gr Sierra Match King, 3.090”
46.0grs H4350, Fed 205M
2773/8.1SD
.5MOA 4 shot group, 3 rounds in bug hole and one slightly right

 
BARREL LENGTH CUTDOWN TEST

Test Load:
162 ELD-M, 2.945”OAL
43.3grs Hodgdon Varget
Fed 205M
Lapua 2x fired brass

Barrel length

31”: 2941FPS/6.8SD
30”: 2916FPS/3.3SD
28”: 2915FPS/7.7SD
26”: 2911FPS/11.6SD

Test notes

a.      Even with rough crown, all barrel lengths shot sub MOA at 100 yards. 26” and 28” were the most accurate, both producing almost bughole groups.

b.    The 26” barrel test was done again using brand new brass, to find the amount of velocity drop off, if any, between brand new and fired brass. The new brass loads produced a velocity of 2874FPS/8.4SD, with accuracy almost equal to the 2x fired cases. After final load development for this barrel was completed, the new vs. fired brass test was conducted again, with both new and fired brass producing groups in the sub .2″ range(.150″ for fired brass, .197″ for new).

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