The main reason wadcutters and semi-wadcutters are used in competition isn't for more accuracy over round nose bullets. The sharp shoulders, or edges, of the WCs and SWCs cut nice, round, full caliber holes while the RNL make a hole that is smaller than caliber diameter. In competition if the line dividing two scoring rings is cut the shooter gets credit for the higher ring, even if the majority of the bullet is in the lower ring. This is also a reason some competition shooters like larger caliber firearms.
I have no problem with using WCs or SWCs for defensive, or offensive, ammo, (in fact I prefer them), but when it comes to reloading the cylinder in a hurry they can be more difficult to load than other nose profiles.
Yes, there is loading data for them in .357 magnum cases. Lymans Pistol and Revolver Reloading Handbook #2 list data for their 141gr. WC #358495 with velocities stated as high as 1382 fps.
