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Posted: 10/29/2004 2:13:50 PM EST
[Last Edit: 10/29/2004 2:14:58 PM EST by GeneSplicer]
It's not bending but the base is getting hammered (no pun intended) because that's all I can think that could be causing it... the hammer. The weapon fires flawlessly and haven't had a single misfire or feed since it's creation this July. I have about 250rds though it so far. Any ideas guys? Thanks.

Link Posted: 10/29/2004 2:29:43 PM EST
Just in that one spot or all the way around? I typically see that edge get roughened and "peened" by the normal action of the hammer dragging across that surface on its way back, and from the firing pin slamming back against the cotter pin in the bolt carrier. It gets rough, but not so much that it impedes function.
Link Posted: 10/29/2004 4:17:23 PM EST
Yeah, that's the only place on the pin. It's just I never seen a pin look like that, then again, most my experience was with the A2 and the carrier ramp covers the pin seat so the hammer doesn't drag across it. Thanks for the info, that's what I thought it was, but didn't know it could cause that happening so quick. Maybe I'll get a custom chromoly steel pin made up...
Link Posted: 10/29/2004 4:19:18 PM EST
An easier solution than getting a special firing pin made up is to use an M16 carrier. The firing pin is better protected on those and this kind of damage doesn't occur.
Link Posted: 10/29/2004 4:56:27 PM EST
The new RRA "enhanced" carriers also went back to have this area shrouded. I guess your hammer may be slightly out of spec.... just a guess.
Link Posted: 10/29/2004 6:33:37 PM EST
Maybe RRA did that is because of this prob... I have a RRA lower and RRA lower parts kit. Hate that my titanium coating is getting marred like that...
Link Posted: 10/29/2004 6:40:28 PM EST
Take a pic of your hammer... specifically the top forward edge... and post that.
Link Posted: 10/30/2004 7:07:08 AM EST
Sorry for the big-ass pic, but you can't see the edge on the smaller ones. Do you think by filing the edge down a little will resolve my problem?


Link Posted: 10/30/2004 9:51:32 AM EST
[Last Edit: 10/30/2004 9:52:45 AM EST by mk1iii]
This is from the hammer releasing too soon and the firing pin getting jammed into that cut out you just posted a pic of.

Two things can cause this. A bad hammer or a mis-timed LL. I suggest you get a new hammer.

Edit... or a third thing. Do you pull the trigger often with the bolt carrier partially to the rear.
Link Posted: 10/30/2004 10:46:05 AM EST
I'm not that quick to pull the hammer when the bolt is halfway, and God I wish I had a LL! I was thinking that the hammer was dragging across the pin seat as the carrier cycles back, just didn't think it'd do that much damage to the pin in so short of time.
Link Posted: 10/30/2004 10:56:43 AM EST
Get an RRA Enhanced carrier from ADCO. They're all I use anymore because of this very problem. It'll solve it, and it will keep your firing pin retaining pin from getting broken to boot.
Link Posted: 10/30/2004 11:39:33 PM EST

Originally Posted By GeneSplicer:
I'm not that quick to pull the hammer when the bolt is halfway, and God I wish I had a LL! I was thinking that the hammer was dragging across the pin seat as the carrier cycles back, just didn't think it'd do that much damage to the pin in so short of time.



Mk1iii is pulling your leg ! Or is smoking crack

Whats happening to your firing pin is normal for an un-shrouded carrier and won't effect/hurt anything. Your thinking is very correct....
Link Posted: 10/31/2004 3:33:23 AM EST
This is a normal function of the parts combination that you have. It is also why the face of the hammer was redesigned a while ago. What you have is an older hammer.

If you look closely at the face of the hammer, you see that notch on the top where the face seperates from the hook as it goes back? You can take a dremel or a file and put a bevel on it, and it will cure your problem. The newer hammers don't have that step, and make a smooth transition with a rounded edge and flow into the hammer back hook. Fix 1=replace the hammer with a new model or file off the sharp edge on the hammer you have. Even the much touted Jewell AR trigger redid their hammers with a beveled edge because the sharp cut face often times will cause the same problem that you're experiencing.

If you look closely at the bottom of your carrier, you notice that the head of the firing pin is open, and at the bottom of the ramp for the hammer as the carrier cycles. The "Enhanced" as well as the M16 carriers have the ramp significantly further back, thus shrouding the head of the firing pin and preventing this problem. Fix 2=get an enhanced carrier.

If you are experiencing this level of damage now, with 250 rounds, you will eventually round off the shoulder of the pin, or you will begin breaking firing pin retaining pins. Although this looks like it may be normal wear, I do not accept it after only 250 rounds. Make a change to the hammer, replace the pin, or replace the hammer or carrier to eleminate this problem.

Just so you don't think I'm talking from the armchair, I just fixed two ARs of my own yesterday, both new builds like yours, that had the same problem. One completely tore out the firing pin at round 153, and the other was causing the carrier to hang up once in a while on the fwd stroke. ALL of my parts were Bushmaster, purchased from a mail order BM dealer.

I hope that this helps. Don't let it go on, you'll only be dissapointed. Gotta love product improvement.

Tom
Link Posted: 10/31/2004 5:57:33 AM EST

Originally Posted By tangeant:

Originally Posted By GeneSplicer:
I'm not that quick to pull the hammer when the bolt is halfway, and God I wish I had a LL! I was thinking that the hammer was dragging across the pin seat as the carrier cycles back, just didn't think it'd do that much damage to the pin in so short of time.



Mk1iii is pulling your leg ! Or is smoking crack

Whats happening to your firing pin is normal for an un-shrouded carrier and won't effect/hurt anything. Your thinking is very correct....



Smoking crack my ass. This is not normal at all. Gene misunderstood when he though I meant during firing is he pulling the trigger while the bolt carrier is still half way back. I was talking about with an unload rifle and dry firing one can cause these marks as the hammer jams against the bottom of the carrier.

He has a bad hammer (and now a bad firring pin that can't keep getting pounded on like that forever without failing one day) or something else wrong that cannot be diagnosed without more info.

Link Posted: 10/31/2004 6:50:24 AM EST
I had the exact same problem and I solved it be getting a shrouded BC from Bushmaster.

get theshrouded BC.
Link Posted: 10/31/2004 1:04:59 PM EST
[Last Edit: 10/31/2004 1:05:50 PM EST by GeneSplicer]
Thanks guys,
mk1iii, that would be possible releasing the trigger with the bolt half-way back, but "normal" reasoning tells me "why in the hell would anyone do that?" Hence I thought during bolt cycle, which also asked "how in the hell?" I guess there are some that do not-so-bright things to there AR's. Think the cheapest fix is try altering the hammer or replacing it. I like my titanium bolt too much to replace it with something else right now... maybe after the coating wears off. Thankd for the help on this issue guys! Hopefully soon I'll post pics of my babe... #50 bi-level SIR, eotech 551, magpul collapsable stock, tango-down foregrip... pics will come soon!
Link Posted: 10/31/2004 2:06:45 PM EST
[Last Edit: 10/31/2004 2:13:13 PM EST by tangeant]
The purpose of this configuration is to prevent hammer follow automatic fire. If your disconnector fails to catch the hammer , the cut in the top of the hammer will catch the firing pin shoulder and hang up the carrier halfway. This is normal ! Yes it will peen the back edge of the firing pin flange but that hurts nothing.

Why did they do it , ramp the carrier and notch the hammer??? Because with an adjustable match trigger and a full shrouded carrier combined with special ATF ammo with high/sensitive primers they can make your rifle a machinegun in less than 5 min with an allen wrench..
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