Anyone who works on firearms even occasionally, where you find someone has used a tapered screwdriver or a phillips, where the bit itself is not a perfect fit. The solution to a slipping screwdriver is too dip the screwdriver bit into a course can of abrasive paste and proceed to take out the screw. It works almost every time.
To make a bit magnetized, wrap a few turns of completely insulated heavy gauge wire around the screwdriver bit. Take both ends of the wire and touch both pos+ and Neg- terminals of a DC car battery. (Do not use AC) A car battery is fine, then hold the wire on the terminals for a few seconds. Make sure there is no bare metal touching the screwdriver or bit.
Whenever you use screwdrivers on a firearm always use gunsmithing screwdrivers the blade is straight and not tapered this insures that the screwdriver won’t walk up the slot and ruin a perfectly good screw. Also make sure the blade fits completely in the slot and fills the slot as well. This will prevent damaging screw heads. I often see collector guns get spoiled just because someone used an ordinary screwdriver on gun screws. The heads are usually torn up.
These can be fixed to look like new with careful re-cutting and filing the screw head and then re-bluing the screw but it is easier to use the proper tool for the job!!