I do not think there is a diff wear wise but I could be wrong I know the marlin lever guns that have shot a lot of ammo through them still have good bores but then even if a deer rifle is 100 years old it will not get the wear a target or varmint rifle gets in only a couple of years. As far as 22's go with the soft lead and low vel of the cartridge you really cannot wear out a barrel unless you have improper cleaning methods. As far as cast shooting goes some have reported success with the micro groove barrel and others have not so that is why the ballard style rifleing came back. If you are going to only shoot jacketed I think it makes no diff if you want to shoot cast I would go with the ballard style as it is more forgiving with cast even though some do say the micro can be made to shoot cast well. Jim
