Ian, I pass no judgement on "blister pack" life styles other than it won't get you to long range success. Regardless of one's passion or methodology for the sport, there is no easy path. You are no doubt correct that cartridge guns are easier to work with in this venue but that does not obviate the capability or potential for ML's to reach out a long ways with success. This was demonstrated a multitude of times in the past, both in the field and in competition. It matters not whether a Sharps or a ML launches the projectile, the BC's of suitable projectiles are too similar to differentiate and the muzzle velocities are likely within 25-50 fps of each other, advantage not necessarily to the cartridge gun. There was a time when "production" ML's were works of art and highly sophisticated; set trigger, vernier sights, false muzzles, and in some paper patch was routine. They shot extremely well. I recall a few years back when Coors was doing the Schutzenfest thing in Golden, Co. that this style of gun would group in the sub 2" range at 200 yards OFFHAND and not necessarily win the competition. These were cartridge guns as I recall, but many Schutzen guns of old were ML's. We like to think we're more sophisticated these days...I wonder about that now and then.
A cartridge case is nothing more than a convenient gasket.