[bedlamite]

A friend from work got his first AR this spring, and has less than 200 rounds through it so far. The cam pin has a burr in where I circled it. You can easily catch your thumbnail on it. None of my guns have a burr anywhere near that big, even after several thousand rounds. I suggested he take it back to the vendor and see what they say, and that it may not have been hardened properly. Has anyone had a similar problem?

 

[owenslee]

Not to that extent on so few rounds. That pin's surface is much too soft.

Cam pins are cheap...get a new one from a quality source.

Who was the vendor...?

Make sure the bolt carrier track is not excessively worn. Hopefully the pin took all the abuse.

Kerry

 

[constructor]

That is a DPMS pin by the color and yes they are soft but, thats not all bad. I would rather replace that pin for $4 than a carrier for $65.
Most pins have an arc where they are slammed by the carrier in each direction, if it is over gassed it will catch it on the front side if the op spring is really strong it takes a beating on the rear.
One thing he needs to check, is there a sharp edge on the carrier or is the metal rolled from the beating?

 

[bedlamite]

Thanks for the info, he got the BCG through M&A Parts. It is slightly overgassed, brass lands between 2:30 - 3:00. I'll take a look at the carrier tonight.

 

[constructor]

interesting, I have heard that M&A is LMTs retail outlet but have not seen the pins with that color come from anywhere but DPMS. Maybe the same company makes them for LMT and DPMS.
IMO it is not a major issue but he needs to swap it out.

 

[Test_User]

C i thought he same thing and I went and check my MA pins and sure enough they are the exact same as the DPMS and the same as ones from another company as well. Wonder if they all get hem from the same place now. They are a pale grey metallic not he blck I am use to seeing.


What angle is your upper throwing./ejecting the cases at? 12 being the muzzle and 6 the butt. Normaly over gassing will prematurely wear the pin. another one is the fit. The loser the fit the more impact the pin gets hit with.