M1A M14 SLAM FIRE

[SSROUFE]

Reloading for the M14, I understand it is common to have a slam fire when the bolt slams shut if you reload with standard primers. I have heard there are heavier duty primers (military grade).
Is there?

 

[jimbo88mm]

CCI makes "military primers" that have a harder cup:

http://www.cci-ammunition.com/products/primers/primers.aspx?id=30

This topic has some controversy. I have seen some swear by these military primers and I've seen others say its not needed.

I reload for a Garand and have been using standard cci primers. When I first started shooting it I would occasionally get doubles and thought it might be the primers but it turned out to be my trigger technique combined with shooting from a bench that was causing it to bump-fire. Since changing the way I pull the trigger the problem has gone away.

Which ever way you go, make sure the primers are seated below flush.

 

[Dans40X]

Fired uncountable rounds thru M1A's & Garands w/Federal primers & torched numerous barrels from the same w/o a single Slam Fire.
Loading medium or long range ammo to jam by single loading could result in slam fires if techniques aren't up to snuff.

A CCI #34 LgeRifle or CCI #41 SmRifle primer cup is manufactured to Mll Spec standards-so to speak!

 

[rminut]

the CCI#34 has more clearance between the cup and anvil. This is what the mil-spec calls for. The cup thickness is the same as the magnum primer.

 

[NorCalMikie]

Out of maybe 5000 + rounds reloaded and fired through my M1A with CCI Mil Spec primers, only had one slam fire.
Single fed without the mag in place, bolt slammed closed, round went off. (rifle was pointed down range)
Won't do that again. :-[
Make sure your brass isn't too long for the chamber and that the primers are seated below the pocket and you shouldn't have any problems.
Brass too long and the bolt can't close all the way or primers seated too high? BIG trouble waiting to happen. With ammo fed from the mag, the bolt slows down enough to keep slam fires from happening.

 

[CADDIE5]

We've used winchester primers and brass and H4895/ IMR 4895 without ever having a slam fire. If you seat the primer properly and use small base dies when reloading it is not a problem.

 

[tjtjwdad]

I would define a “slam fire” as a round going off when the bolt is not in-battery (fully closed/seated). My way of thinking a double is not a slam fire. Slam fires can get real ugly.

There are several things that can cause this; broken firing pin, firing pin intrusion is excessive, the portion of the receiver where the firing pin (the rear portion of the pin) is damaged. There are probably others but these are the ones that come to mind first.

The M14/M1/AR15 has free-floating firing pins. For these rifles I ream the primer pockets and clean them after every firing, otherwise the primer may be just tad high. If you load the chamber from a clip/magazine and then eject the round you will see a small dimple on the primer. Because of these two things, it is paramount that the primers are seated flush and are-not soft/thin. Also, these rifles were designed to be loaded from a clip/magazine. Inserting a round in the chamber and then releasing the bolt under full force seems to be asking for problems, IMO.

Trigger techniques and incorrectly adjusted triggers can certainly cause a double. My way of thinking a double is not a slam fire.

If used Winchester (nickel plated), CCI-200/250 and Remington 9 ½ &/9 ½ M and have never had an issue.

 

[jimbo88mm]

I would define a “slam fire” as a round going off when the bolt is not in-battery (fully closed/seated). My way of thinking a double is not a slam fire. Slam fires can get real ugly.

What you have described is an out of battery discharge. That differs from a slamfire. The slamfire is the round going off when the bolt closes without the trigger being pulled. If the bolt is just a little bit open, then you'll have an out of battery discharge and all that hot gas and pressure goes places where it wasn't intended. The "doubles" that I described in my post were in fact bump fires.

Here's a good video on slamfires with the sks (demonstration starts at 2:00)
[youtube]http://www.youtube.com/watch?v=xj3QtnUWCwQ[/youtube]

Here is an out of battery disharge with an M1 (female shooter)
[youtube]http://www.youtube.com/watch?v=mn0KBzK2Kho[/youtube]

Many speculated that it was a squib load but you can see she removes that last round, and then it looks like she did not allow the bolt to slam forward for the next round. I believe there was a serious mechanical flaw with that M1 because the firing pin should not have been able to move forward with the bolt out of battery. Regardless this is what happens when you have an out of battery discharge. Fortunately the shooter is fine.

 

[Tugdriver]

Hi All,

Recently i was very lucky to purchase a original Winchester M14 '1960.
The rifle is mint condition is very hard to find over here in Belgium.
As a competition shooter i wanted to test the rifle out on a frontrest (for testing reloads)
After only 30 shots i have shot 3 doubles...??
I already red something about the slamfires this kind of rifle can produce..!!
But after a search on the web,i'll found out that i had shot some doubles.
My fault of course...!! I was thinking i was shooting my Grunig & Elmiger,and played with the military trigger.
In fact....the M14 is not a easy weapon to shoot with.
When shooting a second time...but this time shooting in the prone position,with the butt pulled hard against the shoulder
and pulled the military trigger how it should be...firm!! I'd never had a double before!!
Please have a look at the very interesting article.
By the way..i'll always prime my cases with CCI 200 and never had a problem being to soft??
In fact the CCI 200 primers are hard enough for the job !!

Greets to all
Frank

http://www.zediker.com/downloads/14_loading.pdf

 

[JohnnyJohnson]

I usually us CCI Mil Spec primers but during the "Great Primer Shortage" I used regular primers never had one slam fire.

 

[tjtjwdad]

What you have described is an out of battery discharge. That differs from a slamfire.

Thanks for clearing that up. I knew that the out of battery discharge can be disaterous. As far as primers go I've heard Federals are susceptiable to this but I've never tried them because CCI, WLR & Remington have worked so well and are available.

 

[lloydx2]

Yes you can also have a Out of battery slam fire. 99% of the time its reloading error. You can see in the vid that the bolt did not want to close on one round. Most of the time the lugs are 70 to 80 % locked or she would have been hurt. Like Dan I have shot out many barrels useing fed 210m primers in M1 and M1A without issue. But Ive seen it happen. (out of battery)

 

[BaMaverick]

I have an old Navy M-14 and have used factory Federal Gold Medal and have never had a issue. One pull, one shot. I read about possible Federal primer issues, so I when I started to reload, I bought CCI 200 primers.



AccuBrass.com

 

[Dusty Stevens]

You single load a round with no magazine and it WILL happen. Maybe not everytime but it will soon enough. If you feed from the magazine any primer seems to work. I agree the thicker ones may be a better choice but reading the instruction manual is more important here along with muzzle control

 

[riflewoman]

The way to prevent slam fires is headspace control and for that you need a Wilson gauge to set up your dies. Set your die so the case is at minimum headspace. Also military chambers for 7.62mm NATO and 308 Win ARE DIFFERENT in some dimensions particularly in the neck shoulder junction. Smart gunsmiths setup the chamber of M1A rifles with looser headspace (GO +.002) than a bolt.

This may also be an issue with M1 rifles that were reassembled to make them "correct" (as manufactured in 1943). The headspace may not be right. Get it checked if you have one of these.

As for primers. I've used all makes and never had an issue.

YMMV

 

[SWRichmond]

Shot highpower for years with a Garand, single loading, no clip, federal 210M primers, never had an issue.

 

[jimbo88mm]

Never had an issue with standard cci large primers in my Garand.

 

[DonnyJ]

Never had an issue with standard cci large primers in my Garand.

Same here.
Might take a look at this...
http://www.fulton-armory.com/faqs/AR-FAQs/SlamFire2.htm

 

[chkunz]

Reloading for the M14, I understand it is common to have a slam fire when the bolt slams shut if you reload with standard primers. I have heard there are heavier duty primers (military grade).
Is there?

You have received a lot of good response but let me address your question more directly. It is not "common to have a slam fire when the bolt slams shut if you reload with standard primers". In fact, slam fires with the M14 are very rare. Analysis of the few that have occurred usually show that more than one factor is involved; the contributing factors include high primers, soft primers like Federal, firing pin length out of spec, dirty chamber, chamber dimensions out of spec, loading directly into the chamber and not loading from the magazine etc., etc., etc. Also, slam fires normally occur when the round is placed directly in the chamber and the bolt is allowed to hammer the round upon closing. Military style semi autos like the M1 Garand, the M14 and the M16 are designed with floating firing pins and are designed to have the rounds chambered from the magazine. Also, slam fires normally occur when more than one of these factors are involved. Chamber a round in one of these types of military rifles and then eject the round and look at the primer, you will see a small indention from the firing pin.

 

[barefooter56]

Primer pocket uniforming can help with making sure every primer is "below flush" and should be done at every reloading of the cartridge case due to brass flow. Just wanted to add this. Lots of good information here. Use a primer with a hard cup and always chamber a round from the magazine.