09-25-2011, 12:25 AM
I've done some research before getting one to assemble.
Seems as though the sheared lugs can be attributed to the front of the upper receiver being slightly off spec on many uppers.
If you have a lathe to check the flatness where the barrel extension mates up to the upper this is a non issue.
Of the sheared lugs I've read about, all can be attributed to the receiver being off spec, thus the bolt does not have adequate/complete contact with the lugs in the bbl extension.
I true all my uppers as a routine. One less possible problem.
You'd be surprised how "off" this surface can be!
JM.02
Edit: I'm sure putting your rifle on a strict maint schedule couldnt hurt. Bolts DO have a service life.
Seems as though the sheared lugs can be attributed to the front of the upper receiver being slightly off spec on many uppers.
If you have a lathe to check the flatness where the barrel extension mates up to the upper this is a non issue.
Of the sheared lugs I've read about, all can be attributed to the receiver being off spec, thus the bolt does not have adequate/complete contact with the lugs in the bbl extension.
I true all my uppers as a routine. One less possible problem.
You'd be surprised how "off" this surface can be!
JM.02
Edit: I'm sure putting your rifle on a strict maint schedule couldnt hurt. Bolts DO have a service life.