New reloader starting out with .223

[gamestalker]

My primary concern is advice he is getting from his buddy, also a rather new relaoder, as to which primer to use, and that it isn't necessary to use a CCI #41 type, verses standard SR primers.

I'm not a big AR reloader, so I don't have a ton of experience. But my understanding is to play it safe with regard to slam fires, and use the thicker cup less sensitive primer.

Further more, isn't it more likely that a slam fire will occur out of battery? I consider this even more so a risk since he is brand new into the hobby, so the likelihood of some loaded brass that didn't get the shoulders bumped enough, may find it's way into the chamber with a standard SR primer, therefore more susceptible to a catastrophic event.

Please advise me on the overall consensus, and the reasoning as to why it is, or is not a heightened concern to use a #41.

GS

 

[au_prospector]

Good question, watching with interest

I just polished up a few hundred mixed .223 brass myself. First time loading this caliber, will be for my MINI 14. LYMAN simply specifies small rifle primer, so convince me as well that I need #41?

My plan is mixed once fired .223 cases mostly RP and PMC. uniformly sized. CCI small rifle primer. Modest charge of IMR 3031. 55 grain FMJ from Xtreme. Fire on the plinking range with my MINI 14, and repeat. If I like, then I might try to refine a touch for accuracy, but not too stressed about it.

 

[carbine85]

Slam fires in the AR are very rare. Most slam fires will be out of battery.
It's recommended to use magnum primers in semi autos. I have used regular primers without any problems but I typically use mag.
The only rifle I have had slam fires in is the SKS. I've never had one in the AR.
I would concentrate more on the brass and powder charge then the slam fires.

 

[Comrade Mike]

Used regular Winchester small rifle primers for years and not a single problem.

Id argue your friend is actually less likely to make an error as a new reloader. New reloaders tend to be obsessive compulsive and check everything three times over. All the exploded guns and reloading foul ups I've seen were at the hands of "experienced" reloaders who got complacent.

 

[rcmodel]

The way an AR-15 works, an out of battery slam-fire is impossible.
Why?

Because the cam pin rotates the bolt in the bolt carrier to unlock it.
At the same time, the bolt is driven forward out of the bolt carrier, but the firing pin is held in place in the bolt carrier.

So when the bolt is unlocked, the firing pin is too short to project out of the bolt face to hit a primer.

The only time it can reach a primer is when the bolt is fully telescoped inside the carrier, and rotated to lock in the barrel extension.

rc

 

[243winxb]

Use magnum or 34 or 41 primers.

Always load the round from the magazine.Parts guns with mismatched springs may set off a round. The ejector plunger/spring should soften the blow from the closing of the bolt in an AR15, M16. If the buffer spring is to heavy, this can make the speed of the closing bolt to high. This makes it possible for the firing pin to set off the round. Always load a round from the magazine. Other so called "slam fires" are caused by light hammer/sear engagement. (trigger to light.)

Military-style semi-auto rifles seldom have firing pin retraction springs. If care is not used in assembling ammunition, a “slam-fire” can occur before the *bolt locks. (*M1 and M14 only)The military arsenals accomplish this using different techniques and components—including different primer sensitivity specifications—from their commercial counterparts. CCI makes rifle primers for commercial sale that matches military sensitivity specs that reduce the chance of a slam-fire when other factors go out of control*. If you’re reloading for a military semi-auto, look to CCI Military primers.
*Effective slam-fire prevention requires more than special primers. Headspace, chamber condition, firing pin shape and protrusion, bolt velocity, cartridge case condition, and other factors can affect slam-fire potential.

http://www.cci-ammunition.com/products/primers/primers.aspx?id=30 I would not use Rem 6 1/2 or CCI 400 primers RC likes the 400's , i dont.

 

[moxie]

I've loaded quite a number of .223 for my M4gery. I've used both CCI standard #400 SRP and Winchester SRP. Range brass, probably 30+ different headstamps, plus some once-fired Lake City M193.

All went bang.

Never had any slam fires.

But, if you do, rules 2-4 will keep you out of trouble.

 

[gamestalker]

RC, I'm a bit lost here, you say an AR can't slam fire out of battery? So the FP can't jump forward when the bolt abruptly stops against the case head. In other words, if the press were short stroked during resizing or the resizing die wasn't adjusted properly, resulting in a piece of brass not getting the shoulder bumped enough for proper chamber fit, that the firing pin can't jump forward and impact the primer? if this is so, why do most SF's occur out of battery? I'm not doubting you RC, in fact I'm glad I have your expertise regarding this.

This is for my Son, he just took the plunge and has completed purchasing his reloading equipment, and his first load will be for his custom AR build, which has a Timney 3 lb. trigger. I don't want him to get hurt, nor KB a very nice AR, nearly $3K into this build.

Hey, I appreciate everyone's input on this. I'm fully aware that Lyman data and others illustrate the SR primer, and nearly everyone I speak to uses a standard SR primer, but I've always used the #41 primer for the limited and small amount of AR loading I do. I just don't want my Son getting hurt.

GS

 

[joem1945]

I guess I've loaded must be over 10K .223 and shot most all of them. I like CCI or federal sr primers. I have never had a slam fire in any of my AR's. Only slam fire I had was with a faulty SKS.

 

[rg1]

A great series of posts on primers for AR's and semi-autos. Answers a lot of questions.
http://www.sksboards.com/smf/index.php?topic=56422.0

 

[carbine85]

The way an AR-15 works, an out of battery slam-fire is impossible.
Why?

Because the cam pin rotates the bolt in the bolt carrier to unlock it.
At the same time, the bolt is driven forward out of the bolt carrier, but the firing pin is held in place in the bolt carrier.

So when the bolt is unlocked, the firing pin is too short to project out of the bolt face to hit a primer.

The only time it can reach a primer is when the bolt is fully telescoped inside the carrier, and rotated to lock in the barrel extension.

I think this is 100% correct. I remember reading this years ago before I built my first one.

 

[Rule3]

Never have used a a #41 primer in 2 AR's or a Mini 14. Use regular large rifle primers in a AR 10. Most manuals indicate regular SR or LR primers.

The so called Military primers have not been for sale for very long. What did everyone use before the "marketing" hype said to use them??

 

[rcmodel]

I have used standard CCI or Win SR primers in AR-15 and Ruger Mini-14 since 1970.

The only problems I had with them, was when I wasn't getting all the GI primer crimp out, and was smashing primers flat when seating them.

That sometimes resulted in unexpected Doubles when chambering, or firing.
But those were not out of battery slam fires.

The bolt has to be fully locked in battery before the firing pin can possibly hit the primer.

Take the bolt carrier out and study out how it works and you can clearly understand why a out of battery slam- fire can't happen unless the cam pin or firing pin is broken.

The slight primer dent you see on chambered rounds happens after the bolt is fully lock into the barrel extension, and the bolt carrier comes to and abrupt stop.

That allows the firing pin to continue foreword and lightly ding the primer.
But by then, the bolt has to be fully locked for it to reach it.

At worst, you will have an unexpected discharge, down range hopefully!

rc

 

[gamestalker]

Right on, appreciate the information RC. You clearly understood my question, as well as my concern here, which is specifically an out of battery slam fire. My Son is an intently safe and experienced shooter, so if the concern is nothing more than a poorly placed shot down range, that is something we can all live with, should it ever occur.

I extend a big thanks to everyone who provided insight regarding this concern. You've really put me at ease, and now I can stop spending my money on the more expensive #41 for the occasional AR loading I engage in as well.

GS

 

[edfardos]

What rc says. I've had a few doubles with softer primers, but always in battery. CCI 41 or CCI mag primer are your best bets. (Rare doubles were observed with a specific lot of CCI std primers in my experience). Point it down range when closing the bolt no matter what and have fun.