Wichita Lineman on CMP forum sent me a WRA bolt he was having trouble with going into battery.
I cannot post pics on CMP so doing thread here and linking it to his thread there.
What I found is checking locking lug thread lead on the lathe ,the right lug is out of position .0035" (set back )
When I check the bolt face to left/right lug specification I find same thing. .6176" right and .5142" left.
The left lug is actually under spec by .0008" and right is over by .0006"
More than likely it was not running concentric when final thread grinding was done.
So basically when bolts in battery it shifts off center due to lugs not on same lead .
To correct this problem the right lug only needs lapped to reduce its size probably .002 . Hard to do because the bolt will want to shift off center so possible to put .001-.002 shim on left lug so bolt doesn't move off center as much .
Ideally be nice to regrind lugs but Unfortunatly I do not have access to thread grinder or have a good enough tool post grinder to due the job correctly.
Anyway here are the pics showing left / right lug difference .
You can also see shiney spot in right lug corner either receiver not relieved enough on lug corner or product of bolt being shifted off center.
I cannot post pics on CMP so doing thread here and linking it to his thread there.
What I found is checking locking lug thread lead on the lathe ,the right lug is out of position .0035" (set back )
When I check the bolt face to left/right lug specification I find same thing. .6176" right and .5142" left.
The left lug is actually under spec by .0008" and right is over by .0006"
More than likely it was not running concentric when final thread grinding was done.
So basically when bolts in battery it shifts off center due to lugs not on same lead .
To correct this problem the right lug only needs lapped to reduce its size probably .002 . Hard to do because the bolt will want to shift off center so possible to put .001-.002 shim on left lug so bolt doesn't move off center as much .
Ideally be nice to regrind lugs but Unfortunatly I do not have access to thread grinder or have a good enough tool post grinder to due the job correctly.
Anyway here are the pics showing left / right lug difference .
You can also see shiney spot in right lug corner either receiver not relieved enough on lug corner or product of bolt being shifted off center.
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