Problem taking FSB off BCM upper (not taper pin problem)

[trooper84]

I've never had this issue before and it has me stumped... My dad decided that he wanted a rail on his BCM BFH lightweight 16" middy upper. I punched the taper pins out no problem on the front sight base and then ran into an issue when I tried to slide the FSB off the front of the barrel. This is where I ran into issues. The standard F marked FSB seems to hang up at the very end of the lightweight bbl. where there is hump at the shoulder where the barrel threads are. It looks like it should slide right off but doesn't go any further than flush with the shoulder of the barrel threads and the front of the FSB. I can't detect any type of burr or ridge there and it's not like the FSB gets jammed, it just goes to the end and then no more... Never had this issue before and was wondering if I'm just missing something or what? Upper has approx. 800 rounds on it and has had an A2 FH with crush washer on it, all bought new from BCM.

[Ryno12]

Maybe try heating the rings on the FSB slightly & tap it off with a soft hammer.

[markm]

I usually put a good coat of lube on the barrel exterior. Then spin on an A2 flash hider to protect the barrel.... then drive the fsb off with the A2 pointed down on a heavy anvil surface.

[Eurodriver]

Hmm, I was going to post that I have never had that issue removing mine, but now that I think about it I've never fully removed the FSB on a LW barrel before. I just remove the gas tube, slide the FSB forward and install Centurion rails on the OEM nut.

Certainly, the FSB has to fit over that lip because they definitely didn't machine the lip after FSB install. Maybe you have to wiggle it around to get it just right.

[trooper84]

OK... I wanted to post an update and thanks for the advice. I had tried lube and a hammer but got nothing before I posted here. After that, I hit it with more lube, heat, and a bigger hammer. I finally was able to drive it off but not without a struggle. Might be fun getting it back on, but one step at a time...