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Posted: 1/13/2006 4:46:04 PM EDT
[Last Edit: 1/26/2006 5:20:59 AM EDT by wjwill]
I took apart my M4 tonight to get it cleaned up abit. Well as I was cleaning my firing pin, I found that it was rough and mushed out on the edge where it meets the carrier. I post pictures in hopes that someone could explain to me why this is happening.

Pictures of the pin..... and before someone says it, I know I have ugly finger, but it comes with the trade i guess.





Picture of the bolt. See where the pin hits at?



Any ideas on what this is caused by?

Wesley



Link Posted: 1/13/2006 4:49:49 PM EDT
dumb question #1: are you using the appropriate cotter pin?
Link Posted: 1/13/2006 4:53:19 PM EDT
[Last Edit: 1/13/2006 4:54:01 PM EDT by wjwill]

Originally Posted By RED_5:
dumb question #1: are you using the appropriate cotter pin?



Using the firing pin retaining pin(cotter pin i guess you call it) that came with the rifle from bushmaster.
Link Posted: 1/13/2006 4:57:22 PM EDT
either your hammer is knocking the crap out of the firing pin or the firing pin didnt get heat treated and is just plain soft.

see if BM will replace it, if not, buy one yourself. (not that expensive.)
Link Posted: 1/13/2006 5:41:04 PM EDT
The firing pin shouldn't hit the carrier. It should hit the round tail end of the bolt, where it protrudes back into the carrier, when the bolt is in battery. It only hits the back of the carrier, if the bolt is in the unlocked (fully extended) position. Try pushing the bolt all the way back into the carrier, and see if the tail end sticks out into the firing pin channel. I hope that makes sense...

Do you dry fire a lot?
Link Posted: 1/13/2006 5:45:51 PM EDT
How new is this rifle??

I had a similar problem where the hammer was dragging on the FP collar on the BC return.

I bitched about it to Bushmaster and they let me trade in my non-shrouded BC for a new shrouded BC.

cured it for me.
Link Posted: 1/13/2006 6:01:38 PM EDT

Originally Posted By Triple_D:
The firing pin shouldn't hit the carrier. It should hit the round tail end of the bolt, where it protrudes back into the carrier, when the bolt is in battery. It only hits the back of the carrier, if the bolt is in the unlocked (fully extended) position. Try pushing the bolt all the way back into the carrier, and see if the tail end sticks out into the firing pin channel. I hope that makes sense...

Do you dry fire a lot?



The tail end of the bolt does stick out of the firing pin channel. I the only time I dry fire is when I put my rifle back together after cleaning it. I only dry fire it once and that is to make sure it functions correctly.


Originally Posted By Boog:
How new is this rifle??

I had a similar problem where the hammer was dragging on the FP collar on the BC return.

I bitched about it to Bushmaster and they let me trade in my non-shrouded BC for a new shrouded BC.

cured it for me.



The rifle it self is 2 years old but only has around 1200 rounds through it.
Link Posted: 1/13/2006 6:04:58 PM EDT
Well well well... first Colt forward assists, now Bushmaster firing pins ! I never had any such problems with any of my Model 1 builds. I'm glad I didn't pay extra for this level of "quality".
Link Posted: 1/13/2006 6:40:59 PM EDT
Well I don't know, unless it's as Boog said, and the hammer is dragging on the firing pin collar. I also have a non-shrouded BC, and have not experienced this problem, though. Does the firing pin collar extend out past the ramp on the bottom of the BC?

Where is Tweak when you need him?
Link Posted: 1/13/2006 7:28:54 PM EDT
IF it's hammer drag, the tweakster has a nice diagram/pic to show where and how much to releive the hammer (take material off to prevent the hammer from catching the FP spool.)

kinda seems like that's the case to me, but whatdoIknow.

Link Posted: 1/14/2006 12:08:44 AM EDT
Call BM and I'm sure they will send out a new FP. Try out the new one and see if it does the same thing. Sounds like a crappy heat-treat.
Link Posted: 1/14/2006 11:42:08 PM EDT
Link Posted: 1/15/2006 7:19:45 AM EDT

Originally Posted By Randall_Rausch:

Originally Posted By Triple_D:

Where is Tweak when you need him?



Locked up.
Quite literally.

www.ar15.com/forums/topic.html?b=8&f=15&t=220148

It's a sad time for Tweak right now.
Keep him in your prayers.




Holy cow!!! I don't even know what to say.....
Link Posted: 1/15/2006 9:40:43 AM EDT
damn man.........

he'll be missed.
Link Posted: 1/16/2006 2:01:15 PM EDT
Probably due to a poorly made components.
I only use/recommend Colt Bolt Carrier / Bolt assemblies.

Touch base with your dealer or the manufacturer to see what they'll do for you.

Good luck!
Link Posted: 1/16/2006 2:42:51 PM EDT
I don't think dry-firing will damage a pin like those photos. Have you ever had the pin out prior to this? I think it was a production error. Very poor Q.C.In any case I'd replace the pin.
Link Posted: 1/16/2006 3:18:08 PM EDT
[Last Edit: 1/16/2006 3:26:09 PM EDT by Randall_Rausch]
Link Posted: 1/16/2006 11:07:21 PM EDT
Link Posted: 1/17/2006 10:34:58 PM EDT
Damn.... I haven't been on the fourm very long but this sucks about Tweak...... he'll be deeply missed..........

As far as the firing pin is concerned this is the first time that I have ever seen this on an AR15.
Link Posted: 1/19/2006 6:06:08 PM EDT
Could very well be a defective pin too... Its suppose to be hardened chrome plated steel and should actually break before it mushrooms...
Link Posted: 1/19/2006 8:00:47 PM EDT

Originally Posted By theshootersden:
Could very well be a defective pin too... Its suppose to be hardened chrome plated steel and should actually break before it mushrooms...




I just posted all the pics and information in the bushmaster forum. Now lets see what bushmaster has to say about it.
Link Posted: 1/26/2006 5:19:52 AM EDT
[Last Edit: 1/26/2006 5:22:06 AM EDT by wjwill]
I just got off the phone with Jarrod from Bushmaster. I am more than happy with the way he handled my firing pin situation. Turned out to be a soft firing pin.

So a BIG KUDO goes to Jarrod with Bushmaster and Marc(GI_Brat)on this issue.

Thankyou both for all of the help.

Wesley
Link Posted: 1/26/2006 6:18:47 AM EDT
[Last Edit: 1/26/2006 6:24:27 AM EDT by theshootersden]

Originally Posted By wjwill:
I just got off the phone with Jarrod from Bushmaster. I am more than happy with the way he handled my firing pin situation. Turned out to be a soft firing pin.

So a BIG KUDO goes to Jarrod with Bushmaster and Marc(GI_Brat)on this issue.

Thankyou both for all of the help.

Wesley



I kinda thought it was the pin... Good to hear it was somthing as simple as that...
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