I gave up on those bits a long time ago other than for a few jobs.
I now own close to 60 different screwdrivers, flat, hex head, torque, philips and robertson.
All of the flat screwdriver tips are purpose ground for a tight fit that goes at least 90% from one side to the other of the entire slot. Anything else amost always leads to ''galled'' screw heads.
The same thing can and does happen with other types of screwdriver tips as well.
Galled screws = micky mouse gunsmithing.
When I purchase a used firearm and the screw slots are galled, immediate $50 off my offering price.
The last rifle I purchased new was a Ruger 77 and it had galled action screws when it arrived. I sent it back.
I will edit to add that I've perused the bins in yard sales and pawn shops for ''good quality'' screwdrivers, usually at bargain basement prices, to put together my collection of screwdrivers. I've also ruined more than a few learning how to grind them properly.
The one thing most people are drawn to by those sets, is that the bit tips are ground with FLAT sides. IMHO this is a very important thing.
Most off the shelf screw drivers are cut off "V" shapes, which only apply pressure on a very tiny portion of the bit and screw slot.
Of course, there is a good reason for this. Usually people only have a couple of different size flat screwdrivers and they have to fit several diffent width slots, which is OK for most purposes but not for visible firearms screws, which not only look fugly when damaged but can and do cause minor cuts if the galled edges are sharp and protruding.