Sorry for the ignorance, but this came across my mind. Why would someone choose a high power .22 over a .30 and vice versa especially if they were the same grain or near the same grain? The only thing I can really think of is if you want to shoot a .22 in a lighter gr you can do so. Are there bigger advantages shooting a .22 42gr slug vs a .30 42gr slug (Throwing in random grains) such as BC and drag/air resistance? I'm looking at NSA's website and .217 38gr and .30 43.8gr is about 1-2 cents difference per round. Would it be more efficient to shoot .22 42gr vs .30 42gr, same air gun, same barrel, same barrel length (Basically removing all variables). Enlighten me please.