The RMC liner is installed with an Allen Wrench, so it does not have the screw driver slot like the Lyman liner. Instead, it has a socket hole for the Allen Wrench. This acts like a funnel for the flash to enter the liner. The flash hole in the RMC is slightly larger. In addition, the channelin the back side (bore side) of the RMC is 1/8" diameter, whereas the Lyman is 7/64". There's just a better flash channel for ignition with the RMC. As a minimum, I suggest you drill out your flash channel to 1/16" - that's what the RMC seems to be. You can go up to 5/64 if you still don't get good ignition. I have not had any ignition problems with the RMC - if the pan ignites the charge will go off.

See how different the RMC liner is (the one on the left).