:mrgreen:
I have one, kind of.
The Encore 7X307 pistol barrel is 17 3/4" long and a friends daughter shot her mulie with it in rifle form.
Barb has a 22-250 barrel for the Encore frame, I have a 270 barrel and the 209X50 barrel for the same frame. All of these are T/C factory barrels {well, the 7X307 started that way} and all of them are sub MOA barrels with multible loads/bullets.
The grand daughter has a Rossi single shot combo gun with a 22LR barrel and a 410 barrel.
I have found that I need to just 'bump' the shoulder back a hair on the bottle neck cases to have them chamber correctly. I firmly believe that in
break open guns, the cartridge headspaces on the breach and not the shoulder. Without bumping the shoulder back, the fired case is fireformed to the breach face and Encores need about .002 for the locking lugs/action to operate properly. The Contender works the same way, with the same issues. I think the H&R will shoot a bit better if the sized cartridges are sized like that also. As far as a .002 feeler gauge goes, Reynolds Wrap is .002
Some of my 7X307 brass has been fired over ten times and no trimming has been needed, no split, bulged, or 'issues' have been found with any of the cases. I bought 100 307 cases a few years ago when I had the barrel reamed to 7X307 and have never got into the second bag of 50 and some of the original 50 have never been fired. I never 'pushed the envelope' of what the gun/cartridge might be capable of {accuracy kills game, not speed} until I pushed it a bit looking for the 500 yard load. I dropped it back down to 2300 FPS as a few inches elevation at that range did not warrant the flattened primers kubvcabo
Single shots/muzzle loaders can be a challenge but ,,,,,,,, I prefer them over semi auto loaders