One of the nice features about the Challis grip screw bushings is that they are hex drive, rather than having the two tiny slots in the USGI grip screw bushings. It's almost a given that you'll damage the slots when removing a USGI style bushing especially if it's either staked or loctited. Heck, there's a pretty fair chance you'll damage the slot tightening them down.
You'll have none of this foolisness with the Challis hex bushing. Unlike a screwdriver, the hex drive is pretty much a "can't-slip" arrangement. If you plan to use the Challis bushings, you'll need one of these 7/32" nut drivers. Yeah, I was scrounging around in my mechanics tools for a 7/32" socket and drive handle, finally found one and yes it worked okay, but when Challis released these nut drivers, I put my socket set away. The rigid shaft, handle and socket have no wobble and that makes it mucho easier to start the bushings into the holes. The old socket, extension and handle was floppy and I didn't dare try starting threads using that hot mess. Get a Hex Driver and be a professional!