I want reliable feed and extraction. And I want it for the same ammunition used across a number of rifles. I therefore small base size everything I can get a small base die, and I set my dies up with cartridge headspace gages.
The Wilson measures the distance between base and shoulder of the case, does not measure "fatness". In fact, it is deliberately cut wide between base and shoulder so you can drop a fired case in the gage.
This gage was cut with a SAAMI minimum reamer, the port is neat, makes you think you can understand why your case does not fit. Usually cases don't drop in because of expanded case heads, something the sizing die can't fix.
As for accuracy, just give me a break about accuracy. The F Class shooters I know, they full length resize because they want the case to extract as well as feed. No one wants a stuck case. I have had over pressure cases that stuck in the chamber and it is a score ruining exercise to run to the vehicle, find the cleaning rod (!!!)
, knock the case out, and try to get back in the game. In the mean time the wind has shifted, your time is running out, you broke position, and you are under pressure to shoot even though you haven't the slightest idea where the bullet is going to land. Ammunition full length resized is more accurate than the shooter, and this is forgotten in all these equipment discussions. Shooting is a skill. You cannot compensate for poor shooting abilities by expensive equipment and esoteric reloading practices.
Try this, standing shot, 200 yards. See if you can place your shot reliably in the black each and every shot standing. You don't have to hit the 7" ten ring each shot, just hit the black. The black is 13" in diameter. Ought to be easy. It is not. Then, put the same target out to 300 yards and hit the black, each and every shot from any position you want. Actually this is a lot more doable if you shot prone, but then, the criteria ought to be, X ring first shot. After all, with that super duper ammunition, ought to be a pin wheel X.
If you can't do that, the problem is not with the ammunition. Its with the shooter.