canuck4570,
Yep, bolt guns are always allowed and welcome... as long as you're just shooting for fun (what most of us do anyway) and don't expect to bring home any trophy (unless they decide to make a special one for bolt gun) you'd be OK.
The "new" course of fire gives a clear advantage to semi-automatic rifle... and the more magazines you have the better... There isn't much time to thinker around between stages and targets.
Most guys are using some form of AR15, last years we had guys with their 10.5" shorty, guys with their run of the mill M4, and guys with their done-super-dooper race rifle... and most of us got our but kicked by army guys using their C7 and Elcan... so it's not so much the equipment... than the shooter pulling the trigger (and knowning the equipment they use)
As for the MR1, I don't know much about it... it's only been out about a year, but the review are pretty much all positive... as long as you don't like to "customize" your gun. Unlike an AR, there aren't that many aftermarket options for it. So what you see is what you get.
I wouldn't worry too much about barrel life, it comes with a chrome line 1:9 barrel, so for service rifle shoot you'll most likely be bored with the rifle before you wear it out.