I’ve got a bunch of lever guns, with barrels of 16”, 18.5”, 20” and 26”. (I had a Win 1894 Legacy .45 C with a 24” in the past)
I find the pistol caliber ones just fit me best with a 16-18” barrel; handy, well balanced and with enough barrel to have a good sight radius and burn the pistol powder to get plenty of velocity out of those relatively small cases.
Rifle cartridges like .30-30, .35 Rem, and .45-70 seem to work best for me with 18.5”- 20” barrels. Again, they’re handy and well balanced with a bit more barrel for the larger doses of rifle powder. It may be bias because that’s traditional, but I find it the sweet spot. (Which I’ll guess a lot of others did too so that combo became the standard.)
The 24” barrel on the Win 1894 .45 Colt Rifle was way too much barrel for the cartridge. I felt it cancelled out anything positive about the great blend of the .45 Colt and a lever gun, so I sent that packing and never looked back.
The 26” 1895 Marlin .45/70 is cool, and looks awesome with that big octagon barrel, but it also borders on unwieldy. When fully loaded there is a lot of weight out front, and it doesn’t carry like the 18.5” Marlin 1895 Guide Gun does.
I have three Henry’s, all rimfires with a 16” .22 youth, 18.5” .22 standard and a 20” .22 Mag.
These are great guns, I really like them all.
The .45 Colt is my favorite pistol caliber for rifles; big so they’re easy to load and with just enough oomph to smack steel plates without much recoil.
A Big Boy will be a nice addition for you in .45 Colt, try to handle (or better yet shoot) the different ones to see what best fits your wants
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Stay safe.