I did change out all the vent liners in my Lyman Rifles to RMC vent touch hole liners. I got the Allen Head style. Easier to remove and I think I will not swear, might be a hair bigger vent hole. I have no ignition problems. Also some rifles are real picky where you put your primer pan powder. Are you to the outside of the pan edge or tight to the inside of the pan? Some rifles care, others don't.
http://www.rmcoxyoke.com/inc/sdetail...ments/10095/84
These are the ones I replace the Lymans with. While on their site I was looking at current prices for some items. Wow! am I glad I stock piled when I did.