Warning

 

Close
Confirm Action

Are you sure you wish to do this?

Cancel Confirm
AR15.COM
AR Sponsor
6/1/2026 3:29:19 PM EDT
Has anyone with older barrels had issues with ballistic advantage 18” spr barrels not fitting the collar correctly?

I have an older one and just got around to finally build out the Grendel SPR and the Allen engineering collar won’t fit the barrel. Barrel where collar sits is .735” and the collar is .725”. When I bought it, it was advertised to fit an mk12 collar. Thank you.
6/1/2026 7:01:33 PM EDT
[#1]
Six plus years ago I tried two BA 5.56 18" barrels... they shot so bad I damaged my AEM5. BA replaced both but never would answer me as to what was wrong with the two barrels, they were the nitride ones.  I had no issue with collar fitment on those two nitride barrels or the SS replacement... the third barrel shoots ok.

Contact Ron Allen, I believe he can open up that collar for you or maybe have a local shop do it. Turn down the barrel or open the collar.

6/1/2026 8:09:10 PM EDT
[#2]
Thanks. I’m not attached to the barrel. Tried working with their CS but they said it was too long ago to know what kind of specs it was despite the website saying Its for mk12 and collar. I’ll probably parts bin it and get something better.

Sign up to continue the discussion

Create a free account to share your thoughts, follow topics, and connect with the AR15.COM community.

Already a member? Sign In

AR Sponsor