Replacing FSB, how to finish bald spots

AR/M4 AR Technical Discussion
1

I’m replacing the FSB on my LMT upper with a low profile Troy Industries piece.

I’ve heard that the barrel is not finished underneath the the FSB on LMT uppers. The new gas block doesn’t mount at the same locations as the FSB, so there will be unfinished metal showing on the barrel.

What is a good way to temporarily finish the bald spots? Will some gun bluing from Walmart work? The barrel will be refinished with Moly Resin in a month or so, so it will be done “right” eventually.

2

Krylon BBQ grill paint in black will do the job.

3

Hit it with some touch-up blue (Birchwood-Casey brand at Walmart?).

4

Just curious, why not just shave down the FSB? That way you don’t need to worry about refinishing it and it will be pinned!:confused:

5

It was cheaper than buying a Dremel. I’m a student, and don’t really have room for the tools I have already.

But you’re right – I would have just shaved the stock one down.

6

Ah, well that makes sense.