I'm working with Lehigh Defense on making a quality replacement plug for this ML and those that share the same plug. There will be a loose powder plug and pellet plug. I won't rule out one plug for all uses but right now the plan is two.
I've had this ML for over a year now. A few people didn't like my opinions on it but that's normal. I actually love just about everything about it except the breech plug. It's poorly designed, and very cheaply made. The goal is to make a quality plug with better ignition, better steel, and no shims. We have an idea to set the head space right on the plug for a clean reliable ignition source with all powders including BH209 my favorite.
Obviously do to the current design, we are limited to what we can do. I wish we could totally change the plug but that's just not possible. I've drawn up a complete redesign but that would mean barrel threads would need to change and some other things.
I love being involved with making products better. And I'm far from perfect, so any help or suggestions from board members would be greatly appreciated.
My buddy Sabotloader is not a CVA fan, nor does he own one. I still don't think he believes I do 
So we will need a few volunteers to test the plug when ready. But we are in the very early stages and Lehigh Defense is a very busy company.
I'll update this thread when any news happens. All and this was my idea, and in no way will I be compensated for it. I'm good friends with Dave at Lehigh and enjoy being a part of developing new products and being able to test them.
Future plans at Lehigh are as follows in no special order. Improving T/C QR plug. A new premium ML bullet made out of Copper. A Sabotless fast twist ML bullet for shooting paper. And my favorite, designing the ultimate Hunting Muzzleloaders!!