[themauserkid]

I discovered this while doing a pre fire disassembly and cleaning. I purchased this rifle at cabelas recently. I looked at the spot in question under 5x magnification and it almost looks to be a crack. When I took it back to return it they looked at it through a loop and said it was just a scratch. I work on aircraft and detailed parts inspection is nothing new to me and I "think" it maybe a crack. I am considering buying a dye penetrant kit to check it out further but don't know if I can justify the cost. I know a longitudinal crack in this area is unlikely but I'm going to error on the side of caution. Has anyone else seen cracks on these bolts around the lugs not originating from a corner or stress riser?

 

[Job1]

Have you tried cleaning it with a toothbrush and solvent?

 

[Parashooter]

That part is the locking sleeve. It surrounds the rear portion of the bolt. It does not appear cracked. It appears scratched. Note how the rest of the sleeve has numerous scratches of varying severity. Looks like someone put sand in it instead of lube.

 

[themauserkid]

I actually did clean it out, and I understand there are scratches around it, it is just much deeper than them. The cell phone pictures aren't the best I know. It is impossible to see with clarity in this picture what I can with my eyes. I guess I'm just being overly cautious though, it's probably just a scratch.

 

[Ronbo6]

I think that type of indication would fail any type of dye penetrant test, even if it WERE a scratch. It looks too wide to test appropriately.

That location would also be hard to check with a mag particle test. The lug is too close and will screw up the pattern in the shavings.

You MAY be able to find something out using a shear wave Ultrasonic test and an oscilloscope, but you would need to find someone who is REALLY up on his Non-Destructive Testing to even know how to begin doing that type of test. We used to do this to look for damage on the 'back side' (areas not really accessible for inspection) of boiler tubes where I used to work.