Hi Spencer_SS.....
I have one of those H&R Target rifles in 38-55....Most 38-55's have groove dia. running around .377 to .379+...My H&R groove is .381+....The .375 Win ammo is bullet dia. should be .375...The H&R has the strength to handle .375 Win ammo but most likely it won't shoot for beans because of the differance in groove dia....
The main problem with my rifle is that the chamber will only except .379 dia. cast bullets even with neck turned brass...I have read that some of these rifles have smaller groove dia. and shoot cast fine and alot of them like mine don't shoot cast worth a hoot
...One of these days I'll order a reamer to enlarge the chamber..
I can not recommend the H&R in 38-55...