S&W must really be torquing these screws down at the factory now-a-days. Mine was not difficult at all to remove. I disassembled and cleaned the gun before the first shoot, and the screw just came out like every other screw I've dealt with. Easy.
But on my first shooting trip, the screw came a little loose. I figured that was my problem from the initial reassembly. So I cleaned the screw and it's hole with brake cleaner before the next assembly. It has never come loose, not been difficult to remove (there is a little "snap" as it breaks loose), if I use the brake cleaner as my final step after cleaning the gun.
I recently switched to the O-ring method, but I haven't gotten a chance to shoot the gun yet with the O-ring in place. I assume it's going to work well, as so many here have reported. If not, I'll go back to the brake cleaner as last step. Just spray brake cleaner on a Q-Tip and swab down the screw and the hole it inserts into. Then tighten normally.
But it does sound like from the factory, that screw is coming to customers ridiculously tight now. It wasn't that way at the beginning, at least not with my pistol. Were I to get a pistol with a difficult screw these days, I'd put some Kroil penetrating oil around the screw and let the gun sit upside down overnight. Then try to remove the screw. It might help to put a punch on the screw head and tap it lightly to get some vibrations down there to loosen things up. Or maybe put the gun in the freezer for a while to chill it. Or heat it with a hair dryer. Follow up by using brake cleaner to clean out the remaining Kroil. Then install an O-ring. Kroil is pretty good stuff. I use it for routine cleaning too. It seeps under lead deposits in the barrel and makes them easier to remove with a barrel brush. It does penetrate everywhere, including places where you may not want it, so apply to your target area only, and sparingly. Very good product.