Bartlein barrels

Bartlein CFW Barrel Test

By | News/field reports | No Comments

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.

Alpha Munitions brass for the 7mm SAW

By | News/field reports | No Comments

  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!

 

Ready to take the next step? Check out our Custom Gun Builder
0