Border Doc makes good points about loading the 44-40. You have to slightly bell the case mouth, be careful seating bullets to keep from crushing cases.
The 38-40 and 44-40 were made for lever guns and work well with them. They feed well and the thin walled cases expand to make a gas seal with the chamber. .45 Colt cases are thicker and easier to load, But in lever guns using low velocity CAS loads, there isn't enough pressure to seal the thick walled case against the chamber, thus blow back can become a problem. Beginners often start with .45 Colt, many end up with .38 Spec. Black powder is the exception, the bigger cases do well.
My .45 Colt Marlin Cowboy is now a 'diller killer, shooting 300 gr. bullets at max vel with 4227. NO blowback, just a powerful round.
DF
