I see that there are a number of different people or, at least by different names, asking the same question on many other forums. I seen where one person was making a "trial" but, it was going to be quite the machining process and wasn't sure. He never reported back about how it went.
The regulations that many states, most western, appear to be because of the "traditionalist". It happened with bow hunters when compounds first appeared. What some hunters did, was to band together and as a group, went to their state and asked that the regulations for a muzzleloader be changed. It took a group effort and a lot of work for them to succeed. The states changed their definition of a muzzleloader. Here in Michigan it reads: a muzzleloading rifle, a muzzleloading shotgun, or a black powder handgun loaded with black powder or a commercially manufactured black powder substitute.
Some of the other western states, most likely also under pressure from "traditionalists", require that any type of sabot can not be used, therefore at least requiring a conical bullet. No matter how you look at it, they're all loaded from the barrel, using essencialy the same tools and all using an ignition of some sort.
I would recommend that you call and talk to either Mike or Kurt Bellm. Mike has more knowledge of Encore platform rifles than any other person in North America. I'm afraid that you may be chasing a lost cause but, Mike or Kurt are the people you need to discuss this with. They are PRO'S. Home
It may take a lot of work by a lot of people but, working on the state is the only way to make these changes. Those that want to hunt with a flint or cap, can still do so and let others enjoy muzzleloading in the way that they'd like. In the long run, the state itself is going to highly benefit financially. If more people decide to muzzleload hunt because they don't have to learn how to set a flint or other necessities with the more primitive rifles, the state wins!