Don't think that using these will prevent chain firing !! High speed photography has proven that most chain fire occurs at the REAR of the cylinders where all the backflash from nipples spurts sideways into ANY loose or poorly fitting caps...!
Make sure you use #10 caps if indicated.. "Pinching" only exacerbates the problem by providing a flash channel for the hot gases into adjacent chambers..! If #11 caps do not fit snugly use #10's !!!
On the otherhand I use wads in all my revolvers cause they help soften fouling and cushion the powder as well as filling excess cylinder space (the ball should be just level with the cylinder ideally..)
A Great Product..