Slam Fires Using Remington Primers Question

[davester00]

I started to reload .22:

Hornady .223

Varget @ 27.0 grn

PMC brass

and Remington No 7 1/2 Small Rifle Bench Rest Primers.

My rifle:

AR15 Noveske N4 upper with Noveske BGC.

I know that the best primers to resist "slam fires" are the CCI #41 mil-spec.

I know that some manufactures BRPs have a super soft cup.

????Million Dollar Question????

Has anyone had a slam fire in an AR15 using Remington No 7 1/2 Small Rifle Bench Rest Primers?

I am aware of slam fires so I slammed the bolt on one of my reloads and then removed the round from the chamber and noticed that there was a dent on the primer from the free floating pin.

Just asking cause I want to be more than safe.

Please post if you have used Remington No 7 1/2 Small Rifle Bench Rest Primers in an AR15.

Thank you.

David

[Dan Sierpina]

I've used Remington 7 1/2 primers for years in an AR. While slam fire may actually exist, they are so far from common, they can be considered urban legend. Use the 7 1/2 primers, they work real well, and will probably improve your accuracy.

[G-ManBart]

I've used Remington 7 1/2 primers for years in an AR. While slam fire may actually exist, they are so far from common, they can be considered urban legend. Use the 7 1/2 primers, they work real well, and will probably improve your accuracy.

I'm not sure I'd say they're quite to the level of urban legend, but they're definitely misunderstood. If someone chambers a round one time, it's amazingly unlikely to get a slam fire in an AR, but if the same round gets chambered more than a couple of times, then they can go boom. Police departments have experienced this with the increase in the number of uniformed patrols having ARs in squad cars. Years ago the few that allowed/issued ARs typically issued military spec ammo, with the harder primers....no problem. Now they're issuing ammo that's better for the job, but often use softer primers. Every time an officer grabs the weapon from the rack they chamber a round and almost never fire it....so they drop the mag, clear the chamber and put that round back in the mag...do that enough and slam fires can/will happen. When I chamber a round in my AR and don't shoot it, it goes in a bag I keep that I'll shoot the next time I qualify with the gun or want to confirm zero.

[addicted]

ive seen it a few times. my friend has the same gun as me, basically a pieced together A2. nothing special. his reloads that were assembled with a hand priming tool slam fired 2 or 3 times in 1 range session. the ones I made on my dillon press did not. same load, same primers. id start by making sure your primers are seated all the way.

[smokshwn]

+1 on Chris' explanation above.

I understand that primer availability isn't always as good as we would like it. But I have used magnum primers in all of my .223 rds to date and I notice no performance difference from regular small rifle primers. So if you are using the primers in the hopes of load improvement I would say that there is not enough perceived gain by going with a softer primer cup so just stick with the magnum primers. If the softer primers is all you have, then the choice is yours.

[sjs]

Are Federal primers any more likely to have a slam fire than other brands? I just picked up a case for a good price and hope that I can still use them.

[DougCarden]

If the Federal primers are Small Rifle primers, use away with confidence! They are about as good as you are going to get.

DougC

[TwoShot]

I shot 5-6 hundred rounds loaded with Rem 7 1/2 primers through my AR on my last trip to South Dakota. I had no problems with slam fires.

[David Sinko]

I'd be more concerned with the fit of the primer in the pocket instead of the propensity for a slam fire. Federal primers are noted for not giving the tightest fit (especially if you're using Federal's soft brass) and you're more likely to experience gas leaking around the primer than you are a slam fire, at least with primers that are seated to the proper depth.

I use CCI Small Rifle primers and I segregate the rounds where the primers are high. I practice with these and have never experienced a slam fire.

The patrol rifle issue is another good point. My department has been doing the patrol rifle thing for over a year now and we have about six rifles that we all share. We have not yet had reason to shoot anybody or anything, but rounds have been chambered MANY times. Many of the rounds on the top of the magazine are suffering from obvious bullet setback, dented shoulders and even worn rims. And of course the dimpled primers. Most patrolmen can not grasp the inherent dangers of chambering the same round two or 50 times and will continue to do so until we have a problem. In spite of all the ignorance and various disaster factors, we have not yet had a problem. I carry my own magazine with ammo that only I use, so I don't plan to be a part of the problem, but this all goes to show just how reliable the platform really is under less than ideal conditions.

Dave Sinko

[G-ManBart]

I'd be more concerned with the fit of the primer in the pocket instead of the propensity for a slam fire. Federal primers are noted for not giving the tightest fit (especially if you're using Federal's soft brass) and you're more likely to experience gas leaking around the primer than you are a slam fire, at least with primers that are seated to the proper depth.

Hmmmm...they mic bigger than Win primers for me (no CCI on hand to compare). I'm using them mostly in 38SC, but when I have a batch of cases getting old and Win primers aren't seating snug I can switch to Federals and get a couple more uses where they fit properly. R,

[High Lord Gomer]

I have loaded and shot approx 4,000 rounds with Remington 7 1/2 Benchrest Small Rifle Primers. I've never had a slam fire from those.

I did load a few with small pistol magnum primers and got a couple of doubles out of those.

Can you guys educate me as to why a dimpled primer would be more likely to ignite? In my admittedly ignorant mind, it would seem that a firing pin hitting an already dimpled primer would result in moving the anvil less than a virgin one, making it less likely to ignite. Is there a magic point beyond which an anvil moves to ignite the primer or is it the distance it moves that really makes a difference. I know in previous, highly controlled primer testing I was able to pound primers flat with a hammer without igniting them.

[Too_Slow]

H L G, It isn't that the anvil moves (it isn't supposed to) it is that you are making the dimple deeper and hitting the anvil and thus igniting the primer.

Brian

[David Sinko]

We use Remington 55 gr. Power-Lokt for duty ammo. I don't know if this uses the Benchrest primer, but so far they are holding up to a lot of abuse without any problems.

Dave Sinko

[GISMap]

All factory Remington .223 ammo uses the 7 1/2 primer, the 6 1/2 is for the .22 Hornet and .30 Carbine. The 7 1/2 primer is hard cup/"hotter" primer and its actually more mil spec than the CCI 41s, which is not used in any military ammo.

The 7 1/2 is good to go, the AR platform is pretty resistant to slam fires anyway, most of those occur with AKs, M1 Garands, and M14s. I've used countless thousands of Rem primers and never had a slam fire or even a dud.

[WildBill375]

I know this is an OLD thread but just wanted to add that I did have a slamfire with rem 7 1/2's in my 6.5 Grendel.

[Dannybot]

I'm making my way through the reloading section. I've only just started loading, but the very second round I loaded and fired was a slam fire! I almost gave up at that point.

I was using Winchester Small Rifle primers. I went back and looked at the brass I had primed, the primers were inconsistantly seated, so I've been a little more careful, fired about 200 of my loads without another incident.

[dauntedfuture]

Remington 7 1/2 primers are very hard primers. I have shot too many to count and have never had a slam fire with them. The only slam fire I ever had was with Remington 6 1/2 primers which are NOT THE SAME. Experience has taught me that rem 7 1/2 are some of the best small rifle primers out there and they are my go to primers when I can find them with all powders I have tried. You will get a mark when you drop the bolt on a loaded round in most all ARs out there including every COLT M-4 that I have ever been issued; I have read one report of a slam fire of M855 in an M4 but I suspect that the person had an AD and attempted to cover it up as his "evidence" was the small primer mark on an extracted loaded round. At one point, there was a safety message issued telling people not to re-use previously chambered ammo as repeatedly chambering the same round could "sensitize" the primer.

[bigedp51]

Remington ran Lake City Army Ammunition Plant from 1941 till 1982 and loaded the 5.56 ammunition with 7 1/2 primers. These primers are also called baby flame throwers and were designed to light off harder to ignite Winchester ball powders. The majority of slam fires occur when "single" loading a cartridge in the chamber without the magazine in place to slow down bolt velocity. (firing pin inertia) Other problems like a dirty rifle and a jammed firing pin or improperly loaded ammunition will cause slam fires. I have found the majority of slam fires occurs when the ammunition is loaded on progressive presses and not inspecting the loaded cases properly. The military requires the primer to be .006 to .008 recessed below the surface of the case.

When Remington and Winchester ran Lake City they didn't use CCI #34 and #41 primers which are magnum primers with a shorter anvil that requires more force to set off the primer. Meaning sales hype to sell their #34 and #41 primers which can be confirmed by looking at the reloading manuals and looking at the load data for service rifle loading data.

The mini flame throwers in action below and the best way to light off ball powders that use more deterrent coating on their double base powders.

(these pictures below are best viewed when listening to the 1968 Doors song "Light My Fire")

In over 46 years of reloading I have never had a slam fire and I use Remington primers in all my semiautomatic rifles. They were the ones who set the standards for the M1 Garand, M14 and M16 rifles.

Edited August 13, 2014 by bigedp51

[tcoz]

Rem 7 1/2 primers are recommended for AR loading in addition to CCI 41 and CCI 450