weight limits on rifles
There is a pretty good reason for weight limits on rifles and pistols in respect to the Swat magazine world championship 3 gun match (quite a mouthful, actually)
The impression i get from my dad and the other rules makers on the staff is that they have those rules to encourage equipment that would not get the operator killed in an "on the street" situation.
While heavy rifles(which are perforce unwieldy) probably do have some merit in a recreational situation, no army on the globe issues a 14 pound .223 to it's troops, and for good reason, given that the extra weight there could be used for more important stuff, like ammunition and water.
unfortunately, a thompson or an AR in .45 ACP wouldn't be legal, anyway, since the match requires rifles to be in a military rifle caliber (excluding .30 carbine).
Personally, I think requiring the participants to use practical gear in matches is a good idea.