So the whole Black powder case capacity and how it applies today and my getting a 44-40 rifle in.. well.. a long time. and of course all the folks here who have gotten nice clones of BP guns in 45 Colt.. and of course the ammo situation as it applies.
we all know that buying 45 Colt and 44-40 ammo is expensive but thanks to cowboy action shooting is pretty easy stuff to come by. It is mostly all loaded to safe pressures and fun to shoot.
At this point you will find lever action guns in 45 Colt.. which........never were a real thing. Why? well.. the 44-40 was a well developed round with a standard rim.. early 45 colt ammo had a small piss ant rim. A lever action rifle would rip the rim right off.. jamming the gun. Not so with the 44-40 or even the 44 Henry rim fire (but I digress) So the 44-40 was pretty much a 45 colt with a better rim and necked down for a .428 slug. The performance was about the same.. the 45 being a 250 grain slug at 900 fps and the 44-40 being a 200 grain slug at maybe 1,000 fps.
the ugly.. the 45 Colt is a straight wall case. while the 44-40 was necked down slightly.. at the time.. this made no difference except the 44-40 actually fed slightly better. Both the 45 and 44-40 were chambered in all the popular revolvers but the 44-40 came in rifles while the 45 did not.. Sooooo the 44-40 which was actually called the 'frontier' could come in a rifle that held 17 rounds and a revolver that held 6 and the ammo would interchange.. no small thing 500 miles on horseback to a store.
Soooo.. the problem with the 45 was the rim.. the problem with the 44-40 (and 32-20 etc) was a very thin mouth that was easily damaged when hand loading.. Also.. in the late 1900's carbide resizing dies came out but they only worked on straight wall cases. Sooo today I have to lube the 44-40 case to resize it.. not a huge deal but... a deal.
Also.. the 44-40 was designed for a 200 grain slug.. also no big deal in a revolver where I can use up to 300 grain slugs but the lever guns? they are too long.
Case capacity... the 45 and 44-40 are very close as is...........the 44mag ...but you need a strong gun to make a 45 or 44-40 into a magnum.. still.. with powder coated bullets 1,100 fps from a handgun and 1,500 from a lever gun can be achieved.
Sooooo along comes 'Trail boss' not my cup of tea but it works for these rounds. It fills the case to right at the base of the bullet.. it gives decent velocity and in powder coat? well.. that always adds 100 fps
Sooooo yesterday I took the 1873 rifle for a quick test.. at 25 yards from sand bags it basically made one ragged hole. yeah.. I know.. duh? a 30" rifle at 25 yards? But I have seen modern rifles that won't do that.
here is a pic of a max load of Trail boss in a 44-40 case.