cleaning barrel extension?
went to clean a ar that got sighted in and found some heavy baked? on gunk in barrel extension could be carbon,or god knows what used clp and then slip2000soaked that spot for 10 minutes hit it with chamber brush, no luck this gunk is around where the barrel goes into the extension I wasnt sure about using a pick?, but what do you guys use to dissolve this crud, clp and slip ewl dont seem to soften it and is it okay to use a pick to clean debris in this area if its baked on?thanks for your help
Just a GI chamber brush and solvent.
What you could be seing is where the chrome ends and bare steel begins.
Ive seen some barrel extension that had a bit of corrosion in the void from the barrel breech face to locking lugs.Usually a USGI chamber brush cuts it right out of there.
If your talking about build up at the barrels breech face outer edge that has a chamfer down to the barrel extension, you can pick it out if it bothers you.I typically use a Dewey lug recess tool or q-tips the clean the barrel extension after using a USGI chamber brush.
Do keep that area coated with CLP/oil to prevent corrosion and the fouling soft.