There are numerous ways to look at this but here are two. If this is to be a big game hunting simulation contest then nothing less than .40 caliber should be allowed as I think that is the minimum caliber legal for air rifles to be used by the states allowing their use. The .257 caliber rifles used in this shoot are however hunting rifles for varmints, or rams in the flesh, or any hog you put a well placed slug into. I say the more calibers allowed the bigger the event gets. However having said that most shooting competitions do have rules and the organizer has the right to make them. Curious to know what others think.