okay, i've been working on my own guns for about b1 yr after bad luck w/ gunsmiths. I'm getting ready for the AWb to expire and need help finding a pre ban forged front sight base that is pre drilled and I also need help permately attaching my flash hider, I have a couple ideas, one is silver solder, 2  pinned and welded. where can I get a colt, bushmaster or other good front sight base for my project? thanks Billy

You could give these guys a call Yankee Hill Machine

The pin holes on front sight bases are not all the same, even within the same brand.  I've seen a few BM FSBs with different hole locations.  Unless you have access to a drill press, you might be better off selling your postban barrel and buying a preban.

You can have your new bbl drop shipped to KKF or ADCO, send them your flash hider, and have them do the pinning/welding.

Or if you buy a barrel from BM, they will permanently attach the FH for free (if you buy the FH from them).

I've tried doing a FSB swap, and it's not as simple as it appears.