Have a look at the Anvil. Uberti made Remington NMA with a new cylinder proofed for nitro powder. I have a 51/2" barrelled
one and its brilliant. Easy to load with no fillers or lubes. Powder dispenser dumps the correct amount of powder directly into
each cylinder, .457 ball lubed with Alox on top and a shotgun primer in the back. No messy cleaning ritual or pre loading phials.
Just load and shoot. Iv only stripped mine twice in over a year of shooting it and had no problems at all with it. The only
issue if i was being picky is the skinny front sight but thats a NMA thing not an Anvil thing. Check the website out they come
in various barrel lengths to suit your own taste, brilliant. Tim

Oops, just had a look at the Anvil web site and production is coming to an end so if you want one grab one before they are gone.
Shame as they really are a nice bit of kit.