Shouldn't be allowed in a true ML season.
Define muzzle loader.
Sounds like you have a personal thing against in lines. I suggest that you don't use them. If you want to use a side lock percussion cap ML then by all means do so but those are modern when compared to flint locks.
And then you hve the fact that in line muzzle loading rifles are every bit as traditional as side lock percussion rifles. In lines were first patented in 1808. Your argument and bias holds no water what so ever. Basicaly Muzzle loading has come full circle. So quit whining about what other people use and go enjoy hunting and shooting.
The Dreyse needle gun of 1848.