Damaged Barrel Extension Lugs

[UState48]

I recently had a bolt lug shear off in my 224 Valkyrie. It took a ton of force to remove the bolt, and when I finally got it out, I realized that the bottom three lugs in the barrel extension looked like they had been damaged. I'm not 100% sure that the damage did not occur previously, but I think it's pretty unlikely. It's not a new build as the barrel has about 1K on it.

Do you think the barrel is still safe to use?

?

 

[346ci]

I'd scrap it, not worth a kaboom.

 

[UState48]

I'd scrap it, not worth a kaboom.

That’s kinda what I figured. I sent the manufacturer a message, so we’ll see what they say.

 

[whatsupdoc]

Is that a crack on the front take down pin hinge?

 

[UState48]

Is that a crack on the front take down pin hinge?

No, that’s just a nick in the finish of the handguard.

 

[Ledzep]

Mind sharing details of the rifle/ammo?

I wouldn't continue to run it, FWIW.

 

[UState48]

Mind sharing details of the rifle/ammo?

I wouldn't continue to run it, FWIW.

It’s a Criterion barrel in a BCM upper. Bolt was Daniel Defense. I was shooting factory 90 SMKs.

I just talked with Criterion and they suggested that I send it in for inspection/repair.

 

[loveha]

May as well pick up a bolt from them as well.

 

[Yondering]

It’s a Criterion barrel in a BCM upper. Bolt was Daniel Defense. I was shooting factory 90 SMKs.

I just talked with Criterion and they suggested that I send it in for inspection/repair.

Sending it in would be a good idea.

It's hard to tell from the pic, but it looks like the load bearing surfaces of those three lugs are probably damaged and maybe deformed a bit. If that is the case, all the load from firing will be spread across the other lugs, which is likely to break another bolt sooner or later.

 

[roostercogburn98]

Maybe just me, but check this area out too. It almost looks cracked.

 

[Mordamer]

Sounds like you got it squared away. I agree with the others, don't fire another round with it. Barrel extensions are too cheap to risk it.

 

[Powder_Burns]

AR Performance Superbolt
For the SPC casehead, this is your bolt.

 

[UState48]

Maybe just me, but check this area out too. It almost looks cracked. View attachment 7359801

Wow, nice spot! I pulled the barrel last night so I'll inspect the whole upper and see if there's any damage.

 

[UState48]

Sending it in would be a good idea.

It's hard to tell from the pic, but it looks like the load bearing surfaces of those three lugs are probably damaged and maybe deformed a bit. If that is the case, all the load from firing will be spread across the other lugs, which is likely to break another bolt sooner or later.

I removed the barrel to take a closer look and they are most definitely deformed. Glad I didn't fire it with the new bolt.

Criterion has been awesome to work with. Even paid for return shipping.

 

[UState48]

Just for anybody who finds this later in a search. According to Criterion the barrel extension was so severely damaged that they didn't feel comfortable sending it back to me. Criterion replaced the barrel free of charge - pretty amazing customer service considering it wasn't their fault it was damaged.

Daniel Defense also replaced the bolt but I ended up getting a JP from Criterion anyways.

Thanks for everyone's input.

 

[LR308guy]

OP, I have a couple of questions if you don't mind me asking, also please excuse the crude edit of your nice picture.

#1 is that a crack on the front take down pin?
#2 is that a crack on the barrel extension?
#3 is that also a crack in the upper just outside the barrel extension?
#4 what is causing the metal penning?

It just looks like more damage than the barrel extension and bolt lug damage.

thanks,