You will soon find out for yourself. If teh cylinder won't turn, guess what, it wasn't crimped enough and the bullet went forward a bit.
When I shot silhouette with 44 magnum revolvers, we all carried a short dowel and a light hammer in our kit. You were on timed shooting, so coudn't waste too much time. You just quickly tapped the bullet back and got back into action.
You are correct on the 38, in that it shouldn't take much crimp.