I picked up an H&R LBH Commemorative Trap Door; 22" barrel; 45-70.  I shot some of my Sharps loads through it and it functioned okay, but the recoil was punishing.  Thought I'd try a lighter load (less lead) but wanted to check the rifling twist. I've done this before, but not on a carbine with a 22" barrel. I was running out of barrel length before I could get a good reading. Finally resorted to measuring a half rotation and came up with a 1:22 twist. Has anyone else measured one or possible might know the H&R spec on one of these?  I'm not confident in my measurements.
Mike.

I use to use the Goverment Carbine load BP mentioned in both my Origional TD Carbine and Cadet TD. H&R Officers model recoil with the 405 was too much. Used a 330 gr Cast Bullet with Unique just sub sonic.  Nice easy shooting load 22 twist worked fine .

Not sure how the H&R Carbine compares to Origional.  It's hard to shoot any Trapdoor from a bench or prone due stock shape.

Boats

Thanks, JB that's what I was looking for!
Mike.