long range shooting

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


2.920” COAL


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


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.


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.

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