Timely question. I've been looking at a few(now understand that I haven't even gotten my grubby hands on my first auto...YET...but the Ruger seems to be a nicely priced rifle. It's the mag cost I think that's holding me up. I own a few mimis' and it's true that as they are now I'll never hit the black at 100. But at 50 the wife,well never mind,you guys know that story!Anyway,I was always concerned with the build-up of heat in the barrel. I don't want to think what would happen if one would dump 2-3 mags worth of ammo thru one.Any owners have thoughts on heat build-up?