Has anyone encountered any noticeable difference when using these Primers? I have always used Winchester Primers but picked a couple boxes of the CCI BR 4 developed a pretty accurate load from my AR. Figured I buy 1000 small rifle primers(400) not knowing CCI different types of small rifle primers, besides regular and magnum.
CCI BR4 vs 400
- Thread starter BrockPython
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It is recommended to use primers with a cup thickness of .025 with the AR15.
CHOOSING THE RIGHT PRIMER - A PRIMER ON PRIMERS
http://www.sksboards.com/smf/?topic=56422.0
CCI 400 -thin .020" cup, not recommended for AR15 use by CCI/Speer. Good for .22 Hornet, .30 Carbine. See Note 1 at the bottom of the page
CCI BR4 - match primer with a thicker .025" cup.
NOTE 1: According to Speer/CCI Technical Services - Both the CCI 550 Small Pistol Magnum and CCI 400 Small Rifle primers are identical in size. Both primers use the same cup metal and share the same cup thickness. Both primers use the same primer compound formula and same amount of primer compound. They can be used interchangeably.
Cup thickness aside:
"CCI states that Benchrest cups and anvils are selected for exceptional uniformity. During the assembly operation, the operator who meters the primer mix into the cups (or "charger") is chosen from the most experienced workers with an outstanding record of consistency. The BR line runs at a little slower pace to provide time for extra inspection."
I'll see how much difference that really makes when I try my BR2s...
"CCI states that Benchrest cups and anvils are selected for exceptional uniformity. During the assembly operation, the operator who meters the primer mix into the cups (or "charger") is chosen from the most experienced workers with an outstanding record of consistency. The BR line runs at a little slower pace to provide time for extra inspection."
I'll see how much difference that really makes when I try my BR2s...
Small Rifle Primer Performance Pt 3 by Laurie Holland
http://www.targetshooter.co.uk/?p=2662
Small Rifle Primer Evaluation using 6.5 Creedmoor
http://www.targetshooter.co.uk/?p=2662
Small Rifle Primer Evaluation using 6.5 Creedmoor
BR primers is the primer equivakency of weighting your brass and rejecting those outside a certain SD. They will help as much (or maybe even less) than a 1000$ scale for measuring powder, weighting your brass, micrometer dies, etc... It's one among multiple things that makes some kind of OCD disorder necessary to compete at high level in bench rest shooting.
If you can see the difference between a br4 and a 400 in your AR, you've spent a boatload of money on your AR and you're shooting it like a bolt gun.
If you can see the difference between a br4 and a 400 in your AR, you've spent a boatload of money on your AR and you're shooting it like a bolt gun.
Below CCI 400 primers with a .020 cup thickness fired in a AR15 rifle. These primers are designed for lower pressure cartridges like the .22 Hornet and 30 carbine.
Below the anvil was forced through the hole in the primer by residual pressure in a over gassed AR15 rifle.
You need thicker primers in the AR15 rifle for added safety insurance, especially in over gassed AR15 in carbine and pistol length gas systems. The bolt can start to move to the rear while there is still pressure in the barrel. This can push the primer further back over the firing pin and knock the center out of the primer, just like a cookie cutter.
Below from the Sierra reloading manual
Below the anvil was forced through the hole in the primer by residual pressure in a over gassed AR15 rifle.
You need thicker primers in the AR15 rifle for added safety insurance, especially in over gassed AR15 in carbine and pistol length gas systems. The bolt can start to move to the rear while there is still pressure in the barrel. This can push the primer further back over the firing pin and knock the center out of the primer, just like a cookie cutter.
Below from the Sierra reloading manual
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The CCI No.41 primer is thicker in the base as shown below and also has a shorter anvil, this modification requires more force to set off the primer.
When the M-16 rifle was being developed the first ammunition made had Remington 6 1/2 primers and had a slam fire problem.
Remington changed the primer to the Remington 7 1/2 and Colt made the firing pin lighter to fix the problem during M16 development.
NOTE, Remington ran Lake City Army Ammunition Plant from 1941 until 1985 when Winchester/Olin took over until 2001.
ATK who owns CCI took over Lake City in 2001 and convinced the military to use the No.41 primer.
Before ATK took over the 5.56 ammunition used standard Remington and Winchester primers. Meaning for over 40 years no "SPECIAL" primer was used in the 5.56 cartridge.
