Reloading - Slamfire Risk

[samrothstein01]

The other main causes of slamfires are headspacing, and cartridge condition, but that's another sub-forum.

Please correct me if I mispeak on this......But I believe I have established an understanding of one cause/risk of slamfire, and that being that the primer seating and its depth within the case. You do not want the primer to protrude, etc when seating the primer into the casing. You actually want it to be "sunk-in" about .002.

As mentioned above, there are other conditions that could cause this:

1. Cartridge Condition - This one makes sense. A deteriorated cartridge could collapse under stress or not hold properly etc, etc, and this should be noticeable and caught with some common sense and knowing the useful life of a case...right?

2.) Headspacing.....help me out with this one. Regarding the seating depth of the bullet into the casing?

Thanks!!!

 

[Jay]

Headspace is the distance between the bolt face, and the cartridge base, when the cartridge is fully seated in the chamber, and the bolt is closed.

Better explination here......

Fulton Armory FAQ: What is Headspace?

 

[samrothstein01]

Ok, that makes perfect sense, and that cause then has less to do with reloading and more to do with the specific firearm being used. I appreciate all of the info and help!

Thank you!

 

[El Cazador]

Good Morning!

I saw this as soon as I signed on this morning, and I had to find the papers I have on this.

1. Cartridge Condition - This one makes sense. A deteriorated cartridge could collapse under stress or not hold properly etc, etc, and this should

Right, but don't take "deteriorated" to just mean a cartridge in such poor shape it should have been tossed in the recycle bin. A dirty exterior on the casing (fouling, or corrosion on a casing for whatever reason) keeps the cartridge from seating completely in the chamber, thus possibly allowing the firing pin to contact the primer before the bolt has closed and locked up. Even a little bit of corrosion or debris in the inset of a semi-rimmed cartridge can do this. I generally try and have my mags loaded before I go out and shoot, just so I don't drop a round reloading a mag and getting some crap in the inset, and miss it.

2.) Headspacing.....help me out with this one. Regarding the seating depth of the bullet into the casing?

That's part of it. Headspacing can be a problem for the possibility for slamfires, so it's important to make sure the over-all length of the round is at or below the maximum OAL spec'd and is fitting correctly and completely in the chamber. Use a headspacing gauge. Fouling in the chamber itself can keep the round from seating fully in the chamber, too. I read somewhere that headspacing problems seems to appear more often with Match grade barrels and non-military ammunition. Exactly what i'm using.


There was an article in the October 1983 issue of The Rifleman (NRA) about this. A really well done and inclusive article. A copy came with my M1A, and a warning from Springfield Armory that "the use of reloaded ammunition in this rifle voids all warranties". They include M1 Garands in that warning, too. That said, I reload for it, I'm just extra observant and careful when I do.

 

[Robert Richardson]

Possible broken or weak firing pin return spring or soft primers in semi-auto.

 

[mike8170]

Another issue is with military or military style of weapons such as the M16/AR15, series is that the firing pin floats in the bolt. When the bolt slams forward, the pin does also, which will contact the primer. If the primer is soft, this could possibly set it off. I have been reloading for 5 years, and used normal primers in 223, and never had a problem, but recently changed to surplus military or magnum primers due to the availability. Why worry about a slam fire when I don't need to. I use all of my previous reloads in a bolt rifle now.

FYI, I have seen slam fires when a unit I was in recieved new M4 carbines, and the firing pin was slightly heavier, therefore it had enough velocity to ignite the primer when the rifle fed.

 

[tenring]

Welcome to Sinclair International's Online Store

Look for Item UN-8KP, it ain't cheap, but it works like a charm for large volume, or they have one that you use with just a handle for smaller numbers. I finally quit going cheap and wearing myself out and got the kit that I use in a cordless drill. Just got through doing 1035 .223's in once fired Rem. [no crimp} that I got from the Brassman for $81.00 delivered through the USPS. Just check my CC, MidSouth will be shipping 1K of Sierra 69 grain Match Kings that I ordered about 10 days ago. By the time I finish processing the brass the way I want it, I'll have put enough $ back to start looking for primers, or just pass the word and have someone pick them up for me [saves on gas that way].