slam fire

[huntall]

I have a RRA Varmint shot a few factory cheap remingtons 55grain fmjs, remington green and yellow sp, winchester sp and handloads. The handloads produced a slam fire and I was using federal match primers. I read that the Federals were to soft for the Ar rifles. Bought two 40 round boxes of Hornady 52 grain bthps from Graf's Reloading and had a slam fire from them and was wondering if anybody has had the same results or if anyone might have a suggestion?

Thanks
Huntall

 

[scotharr]

Re: slam fire

AR's rarely produce slam fires and the most common cause is improper reloading techniques:
1. Unsuitable primer: soft Federal ones for example. Use CCI or Wolf Magnum instead.
2. Primer should be seated so that it is slightly below the base of the case. High primers promote slam fires.

 

[ponchair]

Re: slam fire

Di<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: huntall</div><div class="ubbcode-body">I have a RRA Varmint shot a few factory cheap remingtons 55grain fmjs, remington green and yellow sp, winchester sp and handloads. The handloads produced a slam fire and I was using federal match primers. I read that the Federals were to soft for the Ar rifles. Bought two 40 round boxes of Hornady 52 grain bthps from Graf's Reloading and had a slam fire from them and was wondering if anybody has had the same results or if anyone might have a suggestion?

Thanks
Huntall </div></div>

Did you have a slam fire or did 2 rounds go off after one squeeze of the trigger?

 

[coldboremiracle]

Re: slam fire

I have a similar problem when shooting 75 gr slugs from my 20" suppressed Ar. I will have two and maybe three go off with one pull of the trigger. I've been told the buffer spring is to weak, among other things, but I believe mine has to do with the suppresor.

 

[samnev]

Re: slam fire

In addition to incorrect seating of primers I have found when a slam fire occurs upon inspection of the brass (unfired handloaded rounds usually) the shooter had was not trimmed and over max length. One time the primers were so badly seated the round would wobble when set on a flat surface. I haven't had any slam fires when using Federal match primers in my AR's, but then I only had 400 of them. I've had zero problems with 52 gr SMK's and only shot 1 box of Federal 77 gr GMM. No problem either.

 

[Tbag]

Re: slam fire

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: coldboremiracle</div><div class="ubbcode-body">I have a similar problem when shooting 75 gr slugs from my 20" suppressed Ar. I will have two and maybe three go off with one pull of the trigger. I've been told the buffer spring is to weak, among other things, but I believe mine has to do with the suppresor. </div></div>

This sounds more of a disconnector issue.

 

[Tbag]

Re: slam fire

Huntall, is it firing upon loading the first round out of a mag, or is it doubling, that is you squeeze off a round and it seems when you let up on the trigger she goes bang again?

 

[huntall]

Re: slam fire

I guess that it is doulbling. First round is loaded from the magazine and when the trigger is pulled two rounds will fire. This is factory loaded Hornady 52 grain bthp. It looks like the bullet may be seating into the rifling. A unfired round seems to stick in the chamder when I try to manually to extract it. And when it is removed there is some engraving on the ogive of the bullet. I also noticed that there was a small mark on the primer from the the firing pin. I'm a little green on the AR and would appreciate any help on this issue. If the bullet is seated to long will this cause a double fire issue?

 

[Unknown]

Re: slam fire

A tiny dent in the primer when the bullet is seated via the recoil spring is normal. AR variants will sometimes fire a second round when the trigger is released after firing a round. This is because the when the disconnector releases the hammer, the sear doesn't catch the hammer in time to stop it's forward movement.

Take the lower off the rifle. Cock the hammer, then pull the trigger (don't allow the hammer to slam into your lower's frame though). Maintain rearward pressure on the trigger and pull the hammer rearward and push it down. The hammer should catch on the disconnector. While you are still holding the trigger in the rearward position, release the trigger. The hammer should come off the disconnector, and catch on the hammer/trigger sear. Sometimes, these parts are out of spec/adjustment, and the hammer won't be properly caught by the trigger. This allows the hammer to go fully forward after it is released from the sear. If that is what is happening, return the rifle for repair along with an explanation. Remington may send you a call tag if you ask nicely..the call tag will save you from paying the postage.

It is just a guess, but I'm thinking that Remington doesn't want BATFE breathing down their necks for making illegal machine guns...

 

[samnev]

Re: slam fire

The slam fire issue has ben a possible problem since the adoption of the M1. Every US rifle since then has a free floating firing pin. Th US uses harder mil spec primers to alleviate the problem. With softer commericial primer you get the dimple because of the free floating firing pin. The problem is made even worse if the primers are seated even slightly higher tahn they should be. Not a problem with mil spec primers. I had a slam fire with my M1A years back using commerical primers. A friend who loads specialty ammo warned me about the problem with possible slam fires and told me to use CCI #34 primers for my M1 amd M1a and CCI #41's for my AR's. They are mil spec primers specically made for the afore mentioned rifles. Never had a slam fire after switching.

 

[Massoud]

Re: slam fire

Another possible cause is a slightly bent firing pin. Try switching out the firing pin for another. Sometimes a slight bend will cause a firing pin to hang up inside the bolt in the forward (protruding) position and not free float like it should.
Justin

 

[Tbag]

Re: slam fire

I guessing a bad disconnector. Did you happen to check if the disconnector sping is inserted into it's slot correctly? If it's a factory built lower call them and let them know they built you a machine gun. You will get a call tag.

I had a Jewell trigger that just loved to double, I will never buy a Jewell anything again.

 

[Cologgi]

Re: slam fire

I have fired thousand of rounds out of multiple ARs, cheap factory, hand loads and better match ammo. I have never had a slam fire or any issue with ammo. What I did have, was an AR that I had purchased used that had a worn sear that would double or tripple tap with just one trigger squeeze. If I gently squeezed the trigger I would have this issue almost every time. If I gave the trigger a hard squeeze to the extent of its travel it would never have an issue. I took it to the smith and is was a worn seer. I bet that is what is going on, or if it is not worn the seer its self is the issue. Its an easy fix if that is the cause.

PS. DO NOT TRUST THE SAFETY ON YOUR RIFLE TILL YOU FIX THIS ISSUE! Good Luck!

 

[coldboremiracle]

Re: slam fire

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tbag</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: coldboremiracle</div><div class="ubbcode-body">I have a similar problem when shooting 75 gr slugs from my 20" suppressed Ar. I will have two and maybe three go off with one pull of the trigger. I've been told the buffer spring is to weak, among other things, but I believe mine has to do with the suppresor. </div></div>

This sounds more of a disconnector issue. </div></div>

I would agree with you except for the fact that it has never done it before I started using the suppressor. If its removed then the problem ceases.

 

[huntall]

Re: slam fire

I don't believe that my problem is from a worn sear since the rifle doesn't have over two hundred rounds through it.
huntall

 

[maggitas]

Re: slam fire

Huntall,

1. As Unknown said you need to perform a function test as prescribed in your AR Manual. Charge the rifle, pull the trigger and keep the trigger held back. recharge the rifle (while holding the trigger down) the hammer should not fall. If it does your rifle has a problem. It should only fire when releasing the trigger and allowing the disconnector to reset.

2.Also I would buy a couple hundred factory produced rounds and and try them in your rifle.

3. Do a thorough cleaning on you Lower Internals. I have had blown primers embed in my lower and caused the problem.

Hope this helps,

Johnny