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November 15th, 2022

Vertical Dispersion Test — Six Primer Types Tested at 500 Yards

primer 500 yard testing node vertical H4895 BRA

Do primer types make a significant difference in accuracy or vertical dispersion at long range? The answer is “maybe”. Here’s one anecdotal study that tracked vertical variance among six different primer types. The tester is a good shooter with a very accurate rifle — four of the six 4-shot groups were under 2″ at 500 yards. This test doesn’t settle the question, but does suggest that it may be worth trying a few different primer types with your match ammo.

Here is a very interesting test for the 6 BRA (6mmBR Ackley) cartridge. Forum member James Phillips, a talented long-range benchrest shooter, tested SIX different primer types from three different manufacturers. To help determine vertical dispersion, James set his target out at 500 yards. He then proceeded to shoot 4-shot groups, in order, with each primer type. Velocities were recorded with a chrono. The photo above shows the results. James says: “I’ll retest the best two for accuracy and consistency with 10 shots each”. CLICK HERE for full-screen target photo.

Wheeler 6BR 6mmBR Ackley Improved James Phillips

As you can see, ALL the groups are pretty impressive. The smallest groups, 1.253″, was shot with CCI 400 primers. Next best (and very close) was CCI BR4, at 1.275″ for four shots. The “flat line” winner was the Remington 7.5, at upper left. There was almost no vertical. If you are intrigued by this interesting primer test, you can join the discussion in this Primer Test FORUM THREAD.

Primer Brand Group Size Velocity Extreme Spread Std Deviation
Remington 7.5 1.985″ 4 shot 2955 FPS 8 FPS 4.0 FPS
Federal 205M 2.200″ 4 shot 2951 FPS 11 FPS 4.8 FPS
Sellier Bellot SR 1.673″ 4 shot 2950 FPS 14 FPS 5.9 FPS
CCI 450M 2.341″ 4 shot 2947 FPS 14 FPS 6.6 FPS
CCI 400 1.253″ 4 shot 2950 FPS 3 FPS 1.3 FPS
CCI BR4 1.275″ 4 shot 2949 FPS 15 FPS 6.9 FPS

CARTRIDGE: 6mmBR Ackley, aka 6 BRA. Parent case is 6mmBR Norma. The 6 BRA is fire-formed to create a 40-degree shoulder and less body taper. Capacity is increased, but the neck is longer than a 6mm Dasher. The capacity is enough to get to the 2950+ FPS accuracy node. Some shooters say the 6 BRA is more forgiving than the 6mm Dasher. The 6 BRA is certainly easier to fire-form.

LOAD SPEC: 6 BRA (40° 6 BR Improved), 31.1 grains Hodgdon H4895, Bart’s 105gr “Hammer” bullets.

TEST REPORT — Conditions, Shooting Method, Loading Method

Tester James Phillips posted this report in our Shooters’ Forum:
Conditions: The testing was done in the morning over flags. The flags never moved or even twitched. I had as perfect conditions as I could have asked for. It was overcast so no mirage and no wind. There were no other shooters, just me.

Test Procedure: Each shot was precisely shot at my pace and centered the best possible using my Nightforce 15-55X scope. I did not use the round-robin method. Each four-shot group with the same was shot at one time. Then I moved onto the next primer. Everything felt right for each and every shot fired today. Of course I could repeat the test tomorrow and it could be exact opposite of today’s test. We can chase this forever. But [soon] I’m going to test the BR4 and 400 primer… for best accuracy and consistency for 10 shots each.

How Rounds Were Loaded: Each load was weighed to one (1) kernel of powder. So I know that’s as good as I can weigh them. Each bullet seating force was within 1# on my 21st Century hydraulic arbor press.

Previous Initial Load Testing: All groups were shot with 31.1 grains of H4895. During initial load testing I settled in on the Sellier & Bellot primer to finalize everything as it showed more promise over the CCI 450 Magnum I also tried. I was actually surprised to have seen the higher ES and SD from that primer today along with the vertical shown. [Editor: Look carefully — one shot from the CCI 450 is right in the center black diamond, stretching the vertical. By contrast the Rem 7.5 had almost no vertical.]

primer 500 yard testing node vertical H4895 BRA

Velocity and NODE Considerations: I was about 5-6 FPS above what appeared to been my optimum velocity of 2943-2945 FPS, so I’ll test 5 shots of 31.0 and 5 of 31.1 and see what happens from there. I can only assume my velocities where higher due to the higher humidity and of course temps were 5 degrees warmer this morning as well. It wasn’t far off but I noticed it.

Permalink - Articles, Bullets, Brass, Ammo, Reloading, Tech Tip 1 Comment »
November 15th, 2022

Have Fun with FREE Turkey Targets and Critter Targets

Varmint Turkey Free Targets Thanksgiving

Thanksgiving is just 9 days away. What better way to celebrate the Thanksgiving season than to practice your marksmanship shooting some bearded gobblers (of the paper variety). Here’s our custom Turkey Target, ready for family fun this fall. This special Turkey Bullseye Target was created by our friend and Forum member Pascal (aka “DesertFrog”). It features a central bullseye with five rings, along with three smaller 3-ring circles. CLICK HERE for FREE Turkey Target.

If you prefer color targets, here’s another turkey target, courtesy of the NRA. Hone your skills on a trio of turkeys. The target features three red bullseyes, centered on the gobblers. You can print the target in black and white, but they look best in color. Click the image below to download a FREE printable PDF file.

NRA color turkey target thanksgiving

Get a Full Set of Animal Targets
For your convenience, we’ve packaged the Turkey Target along with five (5) other varmint/animal-themed targets. These are all offered in .pdf (Adobe Acrobat) format for easy printing.

CLICK HERE to download all SIX targets in .Zip archive.

Varmint Turkey Free Targets Thanksgiving

Permalink Bullets, Brass, Ammo, Shooting Skills No Comments »
November 15th, 2022

Christensen Arms Barreled Actions Now Sold by Brownells

Christensen Arms barreled actions brownells carbon fiber

Shooters starting rifle projects now have a great, high-quality option — Christensen Arms barreled actions. Available exclusively at Brownells, these Christensen Arms barreled actions are available for popular rifle cartridges such as 6.5 Creedmoor, 6.5 PRC, .308 Win, 300 PRC, and .300 Win Mag. All barreled actions are ready to drop into the stock or chassis of the customer’s choice. These Christensen Arms barreled actions are offered in two configurations, Mesa and Ridgeline:

Mesa: Stainless steel barrel and installed muzzle brake

Ridgeline: Carbon fiber-wrapped barrel and threaded muzzle

Rem 700 Footprint Barreled Actions
Because Christensen Arms barreled actions have a Remington 700 footprint, customers can select compatible stocks and parts from a large range of manufacturers, also available at Brownells.

In addition, Customers can easily complete their rifle build with a wide variety of Christensen Arms stocks, bottom metals, muzzle devices, and other parts. To see the full lineup of Christensen Arms parts, visit Brownells.com.

Christensen Arms BARRELED ACTIONS exclusively at Brownells:

Mesa Barreled Actions – Stainless Steel Barrels with Tungsten Cerakote
430-102-968 6.5 Creedmoor 22” barrel $899.99 retail
430-102-958 6.5 Creedmoor 24” barrel $899.99 retail
430-102-971 308 Winchester 22” barrel $899.99 retail
430-102-964 6.5 PRC 24” barrel $899.99 retail
430-102-970 300 PRC 24” barrel $899.99 retail
430-102-967 300 PRC 26” barrel $899.99 retail
430-102-966 300 Win Mag 24” barrel $899.99 retail
430-102-961 300 Win Mag 26” barrel $899.99 retail

Ridgeline Barreled Actions—Carbon Fiber Barrels
430-102-957 6.5 Creedmoor 20” barrel $1,199.99 retail
430-102-956 6.5 Creedmoor 24” barrel $1,199.99 retail
430-102-969 308 Winchester 22” barrel $1,199.99 retail
430-102-963 6.5 PRC 24” barrel $1,199.99 retail
430-102-962 300 PRC 22” barrel $1,199.99 retail
430-102-965 300 PRC 26” barrel $1,199.99 retail
430-102-959 300 Win Mag 22” barrel $1,199.99 retail
430-102-960 300 Win Mag 26” barrel $1,199.99 retail

NOTE: Because the action is considered the firearms for BATFE purposes, all Christensen Arms barreled actions must ship to an FFL.

Permalink Gear Review, Hunting/Varminting, New Product No Comments »