Yep, we could and regularly did. That and butt lengths. We usually did the cheek rests while they were on the course using a rasp. We had loads of them in a big card/fibre box because the next sniper on the next course (it was 6 weeks long originally...) mightn't like the shape of the last snipers cheek rest. Back at the unit the unit Armourers would do it to the rifle he was issued with. You got to know them quite well.