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Posted: 2/23/2010 5:50:39 PM EDT
long story short, my old bolt broke at the cam pin hole. the replacement bolt is extremely tight in the carrier. it will not move with the flick of the wrist.. head space is good. that was the only part changed. unknown maker on the bolt, it came from my aquired parts box.  any ideas how to fix?  no wear in the carrier. gun has about 600 rounds total thru it. model 1 sales 16 inch stainless bull upper .
Link Posted: 2/23/2010 7:48:11 PM EDT
Link Posted: 2/23/2010 9:24:58 PM EDT
Did the bolt come with the Model 1 Sales upper? You might want to get a good bolt.
Link Posted: 2/24/2010 8:38:21 AM EDT
Gas rings can do this too. I still can't tell why one new set wouldn't seat and the next new set did, but that's what happened.
Link Posted: 2/24/2010 9:32:09 AM EDT
Originally Posted By bigjohn1796:
long story short, my old bolt broke at the cam pin hole. the replacement bolt is extremely tight in the carrier. it will not move with the flick of the wrist.. head space is good. that was the only part changed. unknown maker on the bolt, it came from my aquired parts box.  any ideas how to fix?  no wear in the carrier. gun has about 600 rounds total thru it. model 1 sales 16 inch stainless bull upper .


Afterthought - Your bolt BROKE ? Holy hell man, I've swapped out barrels and bolts (always a new bolt with a new barrel) with 15-17K through them and not so much as fracture. Are you shooting FA? Please tell me the 600 rounds you mention were not the only rounds on that bolt. If it were, I suggest calling whoever sold you that piece of "gear" and getting a free replacement.
Link Posted: 2/24/2010 12:40:01 PM EDT
[Last Edit: 2/24/2010 12:43:19 PM EDT by bigjohn1796]
yup, the 600 rounds was the only rounds thru that bolt. it sits most of the time and is over 1 year old. i dont think they would replace it.  it broke at the cam pin hole. it was the bolt that came from mod 1 sales and no, not full auto
Link Posted: 2/24/2010 4:53:54 PM EDT
measurements on machined part of the bolt is .5275, the bore of the carrier is .5315. diameter of the ring pack is .5085. the bolt out of a working gun measures .5280 for machined part of bolt, .5315 for carrier bore, .5020 for ring pack diameter. i can now flick it open by hand now. i manually worked it for a while. the bolt seems to get tight when the machined ring on the bolt starts into the carrier. forgot to try it without the rings on.
Link Posted: 2/25/2010 2:32:41 AM EDT
I suggest calling Model 1 and telling them what happened. Given that as a significant safety issue, they will probably send you a replacement. You might mention that their MP inspection process could use a little tweaking, seeing as yours had to have had a fracture when it shipped. There is no other explanation for what happened to your bolt unless you've been using it as a drive pin in the shop.
Link Posted: 2/25/2010 5:55:34 AM EDT
Link Posted: 2/25/2010 11:44:00 AM EDT
just sent them an email. will post on how it turns out.
Link Posted: 2/26/2010 12:11:38 PM EDT
they said send them the broken bolt and they will replace it.  cant beat that
Link Posted: 2/27/2010 9:20:58 AM EDT
Do yourself a favor.  Order a BCM bolt carrier group and see what happens.

Life is too short to trust yours to a crappy BCG.
Link Posted: 2/27/2010 9:29:33 AM EDT
that is on the list. i just got a bushmaster replacement bolt for now. my other ar runs and runs like forest gump. eats anything you throw in it.
Link Posted: 2/27/2010 10:43:58 AM EDT
"Do yourself a favor. Order a BCM bolt carrier group and see what happens."

What if you have Colt MPC bolts, along with Colt and FNMI BCG's? Still need BCM?

Link Posted: 2/27/2010 9:58:10 PM EDT
[Last Edit: 2/27/2010 10:03:45 PM EDT by 2FALable]
Nope... Colt BCG's are just harder to tell someone to go buy as they aren't as easy to find as a BCM.  I run Colts in most of my AR's.

If that bolt fractured at 600 rounds, I wouldn't trust the carrier that came with it either.  I'd swap the gas rings to see if that makes the bolt move correctly in the carrier and then move that to a spare in the range bag, get a Colt or BCM BCG and run that as the primary.
Link Posted: 2/27/2010 10:53:29 PM EDT
[Last Edit: 2/28/2010 7:05:02 AM EDT by Dano523]
Link Posted: 2/28/2010 9:10:21 AM EDT
after looking at the broken bolt, it looks like half of it has been broken for a while. it is dark and almost looks like it was parkerized when it was new. the other half of the break is shiney and looks recently done.  will atking my parts to the local machine shop to get them magna fluxed work ?
Link Posted: 2/28/2010 3:02:50 PM EDT
Link Posted: 3/10/2010 2:43:36 PM EDT
just got the replacement in the mail. looks good. hope it works .  will pick up a quality piece at the gun show this weekend.
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