Oscarflytyer, ------ With the ability of the 45/70 to be effectively loaded from "mild to wild", the short barrel will produce all the velocity you need in that rifle. -------- I shoot and carry a RUGER #1 with a 22" barrel which would be about equal to an 18" barreled Marlin in overall length. --------- That rifle is just Sooooooooooo great and handy to carry, I simply would NOT want anything longer! -------- Now, as per velocity and barrel length, when I first started hand loading for the 45/70, I approached it like every other centerfire rifle I had loaded for over the last 40 some years -----WRONG!!!!!!!!!!! ---- The 45/70 is a different cat and there is simply ZERO need to push for higher velocities. --------- This is not a long range hunting rifle as compared to say a 30/06 or 300 etc. and if that is your goal, well you will be better served by another caliber. ------------ For that reason, there is no need or good reason to dwell on higher velocity which may be attainable with lighter bullets, say those in the sub 300gr and up to those approaching 400gr. --------- You would be much better served with a good cast bullet with a Wide Flat Nose (WFN) and a weight of OVER 400gr reaching a velocity some where in the mid thousands. ----- I use a 465gr WFN at 1650fps and it is awesome on elk and deer, plus able to handle anything that walks the North American Soil. ----- Some jacketed bullets, for example the Hornady FTX - "gummy nose" are extremely fragile and destructive if bone is hit, while the very light for caliber Hornady homogeneous copper/gilding metal bullet is so light - well below 300gr - it would shed velocity and energy like water off a ducks back. ------ What is the point of a high starting velocity if the bullet will not retain the velocity and energy? ------ So, the short barrel length would be my choice and I'd never worry about the velocity as that barrel length is able to provide ALL you need providing your using a good bullet and more then you need with a bad bullet. --------- Crusty Deary Ol'Coot