I cut mine down to 27" and recrowned it. According to some information in the FAQs , the 45-70 does not lose as much velocity from the shorter barrel as some of the higher pressure calibers such as the .308, 30-06, .270, etc. It still shoots 1" groups with the 300 grn Winchester and Remington ammo. It was simply to long to use in a tree stand that was enclosed.
I have been well pleased with the results.