Colt frequently does not use F marked front sight bases on commercial flattop 20" rifles. Several 6700 HBARs are also built this way. This has been going on since 1994.
You cannot replace a FSB with another one. The holes not interchangeable. You will ruin the value of your barrel if you remove the FSB. The average person does not have the tools to remove it successfully.
No, the shitty orange hockey puck thing sold by Brownells doesn’t not work and neither does any other jig or fixture offered to consumers.
I appreciate the replies, guys. Even the “wrong” above. We’ve already ascertained this and have since moved on. To some people, it matters, hence my question. People sure do get testy over this, eh?