PC9 Rear Sight.

[Mike Bigsky]

I'm trying to remove the rear sight to install optics. My Torx tip just twisted without budging the screw. Will a Torx impact bit work better? Any tips and/or info are welcomed.

 

[NikA]

If you're using a cheap bit from a multi-bit 1/4" drive set, it's very likely to fail when attempting this operation. An impact bit may work better, best would be a high-quality Torx-specific set or Torx driver of the appropriate size.

Also, sights are a typical place for the application of threadlocker. A little heat will burn it off and lower the force required to remove the screw. If you think this Torx is bad, consider the 0.05" hex grub screws used to retain some sight components. With threadlocker, those will round off or strip out every time.

 

[Mobuck]

A common soldering gun/iron works well to get heat on small screw heads.
A couple weeks back, I had to remove an older scope base from a pristine Rem 700. The owner said the 'screws were glued' so I assumed the worst and immediately went to the soldering iron followed by my best torx bits with a couple of whacks from a brass hammer prior to applying twist. The screws didn't exactly fall out but most certainly didn't stress the shoulders of the torx interface.