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11/22/2017 10:05:29 PM
Posted: 7/17/2004 5:03:46 AM EST
Is this wear normal by the recess for the locking lug? I am afraid my bolt is trying to lock up too soon and the cam pin is rubbing on the inside of the upper just before it gets into the recess. This upper has alot of round through it so I don't know if this wear is normal?


Link Posted: 7/17/2004 5:40:27 AM EST
Fairly common. Some I have have a groove cut in them there from shooting a lot. Seems worse on barrels shorter than 20" on my guns.
Link Posted: 7/17/2004 5:44:18 AM EST
I realy dont think it is a problem. As long as it is still locking up it should be fine...
Link Posted: 7/17/2004 6:21:27 AM EST
[Last Edit: 7/17/2004 6:22:28 AM EST by scottryan]

Originally Posted By j3_:
Fairly common. Some I have have a groove cut in them there from shooting a lot. Seems worse on barrels shorter than 20" on my guns.



That is what this looks like, a grove. It has an 11.5" barrel so that might explain somthing. The upper does run fine.
Link Posted: 7/17/2004 7:53:10 AM EST
[Last Edit: 7/17/2004 7:53:45 AM EST by xcpd69]
Remember, with the short gas system on the Carbines, the gas is tapped off at DOUBLE the pressure of the full length gas system rifles. This DOES cause more violent cycling of the bolt and carrier, which quite possibly MAY have something to do with this.

I'm no expert, but it makes sense to me.



Lonny
Link Posted: 7/17/2004 8:19:46 AM EST
Its normal and I have a little more wear on my carbines as oposed to my full size rifle,dont worry about it as long as its running fine.One of my uppers is 12 years old and after 2 rebarellings and a bolt change and hammer change and thousands of rounds its still running nice and smooth.
Link Posted: 7/17/2004 11:11:45 AM EST
[Last Edit: 7/17/2004 11:13:38 AM EST by gregw45]
Normal. I recall Tweak stated this kind of wear happens during extraction.

The cam pin does contact inside the upper... it's what keeps the bolt from rotating when the bolt locks to the rear or when first contacting (while chambering) the top round from a magazine.

Link Posted: 9/24/2004 11:13:57 PM EST
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