Slamfire - What do I need to know

[Garanditis]

I realize slamfire isn't a phenomena limited to M1's, but I have few questions. First, does anybody know if topic been addressed at length here (or on another forum) when talking specifically about about M1's? I did some Google and Youtube lookup. Found a Canadian fellow whose gun blew up in his hand on video, but lucky for him, all it did was destroy his stock. Guilty party in his situation was the steel-cased ammo Cabelas sold to him. And from my subsequent searching, "bad/wrong ammo" is generally the cause of slamfires in M1s. Also saw headspace as a candidate. I am concerned about this. My plan is to try to secure some M2 Ball. When that's not available buy the new ammo made for the M1 Taking my M1 to Orion 7 this week to have it checked out before I fire. So the gun should be good when I pick it up. I feel like ammo would be my only issue at that point.

Any ideas?

[RAMMONT]

I can't wait for this one, I'm sure that the usual guy will come along and tell us about Federal primers and the conspiracy between the NRA and the military but in the mean time you can check out the other M14 forums, they may focus on the M14 but the slamfire issue is the same for both the M1 and the M14.

Conspiracy theories notwithstanding, most people agree that the main causes of slamfires are receiver wear and/or improperly seated primers. Firing pin tips can also be a problem, if the tip becomes too pointed then it can cause pierced primers and slamfires.

[Phil McGrath]

Yea, shoot good quality ammo and stay away from the steal case ammo. The varnished coating gums up the chamber and while the steal used in the case is mild it is still not as soft as brass casings are so there is less cushioning as the rifle chambers. Gummy build up in the chamber then the case pokes out higher in the rear, bolt doesn't completely close, now your asking for a out of battery event.


If you don't reload get with a mentor and learn.

My .02

[Garanditis]

I'm an engineer, so the idea of eventually reloading, making my own, is interesting. But Phil, as you say, I'd have to agree, a mentor is a must.
Excellent points gentlemen. I guess, assuming my gun's a GO, keep it clean and well lubed

[RCS]

Good reading in Billy Pyle's book "The Gas Trap Garand" on page 126 "A Cautionary Tale" of an out of battery "slam fire" from a broken round firing pin in s/n 42664 gas trap rifle. I have seen an aftermarket trigger pin snap as the action was chambering a cartridge on an M1A, which also resulted in an "out of battery slam fire". There were one or two gunsmiths that installed a return spring on the M1 firing pin. One of the first questions the rifles manufacture will ask you (after reporting a out of battery slam rifle) if you were using reloads or factory cartridges

[Garanditis]

RCS ... I had read that the firing pin was heavier in the initial Garand designs and by the T31 design, a lighter firing pin had helped solve early slamfire issues. Also, from an interesting article in Fulton Armory, the author mentions possible issues when single loading. Without the clip in there (and the associated friction), when an operator lets the bolt "fly home" freely, it will move forward with a greater velocity than had the clip been in there (makes sense). I thought this to be an interesting point.

[jak]

The amount of friction on a bolt caused by ammo and an enbloc versus no ammo and enbloc is insignificant. All of the points stated in previous posts are more likely to cause an out of battery fire than a slight decrease in friction on the bolt. I have single loaded thousands of rounds in practice and matches without using an enbloc and never had an out of battery fire. Many of my competitors also single load without an enbloc and never had a problem at a match. If you feel safer using a modified enbloc for single loading, go ahead.

[TJT]

In over 30 years of shooting the M1 rifle I have NEVER experienced a slam fire, nor M1 thumb for that matter. Use quality ammo that is designed for the M1 rifle. When you start loading your own, make sure the primers are not "high" seated. Can a slam fire happen? Yes. What is the probability of having one? Slim to none as long as the rifle is in good shape and proper ammo is used. You're worrying about a virtual non issue.

[Phil McGrath]

I realize slamfire isn't a phenomena limited to M1's, but I have few questions. First, does anybody know if topic been addressed at length here (or on another forum) when talking specifically about about M1's? I did some Google and Youtube lookup. Found a Canadian fellow whose gun blew up in his hand on video, but lucky for him, all it did was destroy his stock. Guilty party in his situation was the steel-cased ammo Cabelas sold to him. And from my subsequent searching, "bad/wrong ammo" is generally the cause of slamfires in M1s. Also saw headspace as a candidate. I am concerned about this. My plan is to try to secure some M2 Ball. When that's not available buy the new ammo made for the M1 Taking my M1 to Orion 7 this week to have it checked out before I fire. So the gun should be good when I pick it up. I feel like ammo would be my only issue at that point.

Any ideas?

It hasn't been discussed here because your really the first too bring it up..... There are a few more issues than just "Bad and Wrong Ammo" that cause a out of battery firing. You can check out some of the other forums and seek out the person known as Slamfire or Eagle1 if your looking for the real down and dirty-nitty-gritty details. On a side note he has a very detailed list of 03 failures for both single heat teat and double heat treat rifles long after the Army quite collecting info.

[M1 rookie]

I found the following article helpful. Just search for this title in your browser...
M1 Garand Slam-Fires: Potential Causes & Solutions

[Smokey]

Improper headspace (too tight) can lead to a slamfire. If the case does not fully enter the chamber without resistance, the firing pin can hit the primer hard enough to fire the round out of battery.

[RDS]

American Rifleman magazine did three excellent articles on slam fires . THE MYSTERIOUS SLAM FIRE October 1983 pages 42,43,73,74,76,77,78,79 and 80. MORE ON SLAM-FIRES Jan. 1984 page 62. M1 SLAM-FIRES Nov. 1991 pages 59 and 60. All three dealt with slam fires in M1 Garands and M1/As.

[David Milisock]

I realize slamfire isn't a phenomena limited to M1's, but I have few questions. First, does anybody know if topic been addressed at length here (or on another forum) when talking specifically about about M1's? I did some Google and Youtube lookup. Found a Canadian fellow whose gun blew up in his hand on video, but lucky for him, all it did was destroy his stock. Guilty party in his situation was the steel-cased ammo Cabelas sold to him. And from my subsequent searching, "bad/wrong ammo" is generally the cause of slamfires in M1s. Also saw headspace as a candidate. I am concerned about this. My plan is to try to secure some M2 Ball. When that's not available buy the new ammo made for the M1 Taking my M1 to Orion 7 this week to have it checked out before I fire. So the gun should be good when I pick it up. I feel like ammo would be my only issue at that point.

Any ideas?

In my opinion a properly maintained M1 Garand has as close to a zero chance of a slam fire as any self loading rifle ever made. If you have a concern have the rifle checked out and discuss the issue with your smith. Having shot what's now called CMP shoots and working at my clubs I been around tens of thousands of rounds fired in the M1 heading on to 40 years now with zero slam fires. With that said always keep your muzzle pointed in a safe direction it's basic safety. The ammo was a mix of CMP and reloads, I shoot reloads and I also single load.

I have one time seen an AR 15 A1 double and then triple on the same day and inspecting the reloads I suspected improperly seated primers. The rifle functioned fine with factory 223.

[Garandimal]

Slam-fires in the M1 rifle - are generally caused by the free-floating firing pin, coupled with soft, non-mil primers.




GR

[TJT]

I've used all the primers over the past 45+ years--CCI, Federal, Winchester and a couple of others that escape my memory. I've never had a slam-fire with any of them, even the so called "soft" primers whether feeding from the clip or single loading. It's all about the condition of the machinery and seating depth of the primers.
Jon

[lapriester]

Slam-fires in the M1 rifle - are generally caused by the free-floating firing pin, coupled with soft, non-mil primers.




GR

Well, not really. They are most often caused by high primers. BTW, primers, for the most part, are not hard or soft. Mil spec primers simply have an anvil design that resists floating primer strike. For example, CCI magnum primers have exactly the same cup design and "hardness" as their milspec primers do but have a different internal anvil.

I've been using standard CCI 200 primers in my Garand reloads for close to 20 years and thousands fired. Not one slam fire has ever happened. Just be certain your primers are seated deep and you always clean your pockets and uniform ex military cases before reloading them. Do that, and slam fires will be a non-issue. Hell, they don't hurt anything anyway contrary to urban myth to the contrary.