RMR 69 gr OTMs

[grizzman]

The load in LC brass are 2.245" in overall length. I've got about 25 more of them, so I'll try them through a very low round count Centurion CHF mid weight and a BCM BHF gov profile barrel that does really well with everything.

[markm]

Shot a couple of 75 gr MOAish groups yesterday with H322 and VV N135. Both running at 2700 fps out of a 20" Bolt gun. Both showed horizontal stringing. I'm going to stick with the Vhitavouri load since I have a lot of that powder.

[BuzzinSATX]

MarkM, anyone else…

What primers should I use for AR’s?

I see AR specific CCI and Winchester (#41 NATO), but not for the other brands. Does it matter?

I’m looking at Unis Ginex, Federal, Remington, Fiocci, and some others.

Are there any I should specifically avoid?

I’ve been mostly loading Federal Gold Medal AR (expensive) and Winchester #41’s. Can I use the others? Thanks!


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[markm]

I'd use whatever you can get. My current batch of CCI 41s is squirrely. Big velocity spreads, and a few failures to fire. We run an old stock of WOLF SRM primers that are great. Also have some Fed AR Match.

[BuzzinSATX]

I'd use whatever you can get. My current batch of CCI 41s is squirrely. Big velocity spreads, and a few failures to fire. We run an old stock of WOLF SRM primers that are great. Also have some Fed AR Match.

Thanks. So the whole “slam fire”
issue isn’t really a thing?


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[grizzman]

The AR's bolt can't get stuck in a protruding position, which is a common cause of slam fires. The firing pin does bounce off of the primer with enough force to make a small dent in it when the bolt is locked into position. If the cup too soft, this impact can set off the primer.

CCI's 450 has a cup with the same thickness/hardness and flame output as the CCI 41. The CCI 400 is used by a lot of people, but I prefer to use the 450 for everything but close range ammo.

[markm]

Thanks. So the whole “slam fire”
issue isn’t really a thing?

Nope. Some pistol primers will slam fire. I accidentally put a Ginnex pistol primer into a "one-off" round just to get the thing off my bench. Totally brain farted that it might be a pistol primer.... Anyway it slam fired out at the range. Fortunately pointed in a safe direction.

[1168]

Any “magnum” SRM will have a thicker cup like CCI 41s. As long as you’re following the other rules of reloading any small rifle magnum primer will do, so far. Just plan on reworking when changing brands or lots. If you’re buying them by the hundo, stay away from max or set aside a few from each lot to chrono before going bulk.

I haven’t tried the Ginex’s yet in a rifle. They’re pretty hard in pistol flavor.

[triggerjerk]

I got into primer pocket uniforming for bolt guns a ways back. Don't know if it helped with accuracy then, and I'm pretty sure it doesn't with AR now. But it does cut pocket close to max depth to help me avoid high primers. They say it is a one time thing. I think I noticed in my .308 that the pocket face did get pushed ever so slightly rearward upon firing. For my ARs, yep, it's a one time thing. Yep, I prolly waste a lot of time in my processes....

I guess what I'm trying to say is that I've used a lot of cci400s no probs (knock wood)....

[MarshallDodge]

I've probably used all the different brands of small rifle primers in an AR, and have never had a slam fire. The CCI 450, which is a small rifle magnum, works well and is what I am currently using.