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Page AR-15 » Troubleshooting
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Posted: 3/11/2006 11:16:14 AM EDT
Thank you for all the help. I am going to test the magazine tomorrow and see if it stops the "Slap fire"
Link Posted: 3/11/2006 11:42:56 AM EDT
[#1]
This is called a "slam fire".  When feeding from a magazine, the friction of stripping out the round, and the additional inertia of the round its self slows the bolt carrier group (BCG) as it's forced forward by the recoil spring.  Without this slowing, the loose firing pin is slamming into the primer with sufficient speed to fire the chambered round.  Either feed it from a magazine, or ride the BCG down with the charging handle and use the forward assist if necessarry, but don't drop the BCG on an already chambered round.

I don't want to bust your balls about this, but this isn't an accidental discharge, it's a negligent discharge.  The weapon is performing nominally, but YOU are messing up.  
Link Posted: 3/11/2006 11:52:28 AM EDT
[#2]
I empty load by sliding a mag in and hitting the release with the palm opf my hand.  If the gun can't handle that, it is defective.  I will not accept having to baby any of my gear.

Furthermore, the Army has conducted tests which have debunked the slam fire theory.  With 165,000 US troops in Iraq, they have not had a slam fire problem, despite repeatedly chambering the same rounds.

What I will say is this.  Load from the magazine.  It is abusive to the weapon to let all that mass slam around like that, and it is most likely the cause of your problems.

Get some damn training.  A good instructor will teach you many things that can't be learned on the errrornet.
Link Posted: 3/11/2006 11:59:49 AM EDT
[#3]
Read closer. He's slaming the BCG forward without a mag in the rifle and the round already in the chamber. Nothing to slow it down. Firing pin slams forward and on occasion it fires the round.

Slam fire was the reason that they changed the Firing pin on the early M16's if I remember correctly. I'd have to go pull the info back up to be sure. But I do remember a pic of a firing pin with a spring as an attempt to fix the problem. In the end they went with a lighter pin IIRC.
Link Posted: 3/11/2006 12:02:25 PM EDT
[#4]
I read it again and edited my post.  He needs to get a magazine in their.  Not much point to an M4 if you aren't going to use a magazine anyway.

As far as slam firing, if you are using a mag, it shouldn't be an issue.  Ever.
Link Posted: 3/11/2006 12:03:42 PM EDT
[#5]
+1
Link Posted: 3/11/2006 12:10:38 PM EDT
[#6]
+1

That extractor is designed to have a round slide up onto the boltface from the bottom, NOT to snap over the rim of an already chambered round.  Not only can this cause slamfires but it may eventually break your extractor.

If you want to be happy for the rest of your life, don't get an ugly woman and make her your wife.

Just always load by feeding the 1st round from a seated magazine.
Link Posted: 3/11/2006 12:49:12 PM EDT
[#7]
Hey yall thanks for the help, i know i needed to use the magazine but i figured a few round like this wouldnt hurt. The magazines came in today after i posted so that is not an issue anymore.

As far as the training, i used to work for the police department back home as a volunteer and worked withthe AR15 on a regular basis, i have tactical training and numerous hours of safety training from them, i was in the US Army and we were tought a lot of that in basic, so yes i know i have to use a magazine. I was just wanting to make sure that this couldnt be a result of putting something together wrong as this is my first build on the lower.

Thanks for all the help and constructive critism. I am a noobie and i will admit i was wrong. But again thanks for the quick response form all.
Link Posted: 3/11/2006 3:50:47 PM EDT
[#8]
Post locked by Owners request to allow it to fade off into oblivion.
Link Posted: 3/11/2006 4:00:00 PM EDT
[#9]
Post locked by Owners request to allow it to fade off into oblivion.
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