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View Full Version : Bolt carrier key staking

Krinkov556
04-22-2004, 07:06 PM
I posted this question on AR15 general discussion. Think I might get a better response from you guys.

Noticed on BM bolt carrier that the key housing shows localized fractures directly adjacent to staking marks - on either side of stake but only on gas key housing. Appears that staking process resulted in key housing localized fractures due to material strain from staking impacts. Is this common? Any concerns regarding material breaking loose and damagng upper receiver?
RJ Shooter
04-22-2004, 09:00 PM
It's very uncommon for new carriers & bolts. I don't know about the older ones. The reason I say this about the newer ones is because they are magnetic particle (MP) tested for metal strength.

Also, how can you be sure that this is a Bushmaster bolt?
Krinkov556
04-22-2004, 09:26 PM
Your point is well taken with regards to true corporate identity of carrier. It was purchased from an individual and not directly from BM.

Seems there are two approaches in general to staking the carrier key. Stake on the top of key and stake on the sides of the key. Approach seems to vary from carrier source to carrier source. Those that stake from the side would appear to risk the exact conditon I tried to describe where fractures can be generated between the outside edge of the key and the interior key screw hole in the area of the screw head itself. From what I can see with a 10x there is only evidence of fractures in areas that are not in load path. Only concern is possible dislodging of fractured material.

This seems to be a condition that is rooted in the staking process only and no other parts of this specific carrier assy show any other flaws

Was curious if the anyone else has seen this type fracturing of carrier key staked areas especially since staking from sides of carrier key is common practice.

Edit;
Here's photo to illustrate the condition. This is not my bolt carrier assy but they both are staked in the same fashion.

http://www.gunsnet.net/album//showphoto.php?photo=27273&password=&sort=1&size=medium&cat=500&page=1