I think it would definitely be a good idea to use gas checks. and for the record, she has a bolt action rifle with a 34" barrel.
Our interest in this is for two reasons: first to make huge clouds of smoke for giggles, and second to see if we can't lower the cost of shooting and reloading her big gun in these hard times. She casts her own bullets, reloads just about everything, and is looking into making black powder. (and all this after she gets done with the house work, the kids and the critters).