On North American game, all of the .50's seem work better than the .45's. Nothin is changed there. The smaller bores were broght out for shooting longer ranges. The typical 36" twist of the .50 2-1/2" cal Sharps didn't stabilize the bullets well, which restricted it's effective range on buffalo to around 300yards. To that range, it was better than any smaller bore. The 3-1/4" .50 cal case was invented by Winchester, not Sharps. It was never Factory chambered in Sharps rifle.
The .50/90 is much easier to shoot with smokeless as well as black powder loads. By this, I mean the slightly shorter case is easier to produce accurate ammo in.
: I've had both, and the 2.5" case is the way to go.
: A friend, who owns my old 3-1/3" Sharps, routinely uses the 450 Lyman bullet with 110gr. of AA 4350 or 3100, not sure which, for well over 2,000fps. The load is listed in the Accurate Arms powder handbook. It polaxes moose, but then, so does a 550gr. RCBS bullet from the .50/90.
: Due to the cavernous case, smokeless loads don't bulk up well, which promotes the shooter into using very large charges of very slow burning powders. With a narrow butt plate, recoil is memorable. A shot-gun butt is recommended.
: One load that shot into 1.3" @ 100 meters(tang and pinhead sights) for me with the 3-1/4" case, was 63gr. 3031 with plastic bead filler and a 550gr. RCBS cast bullet. This made 1,760fps in my rifle and had all the recoil I desired - and more. It is listed max for the #515141 Lyman bullet in the Lyman Cast Bullet Handbook, but I had no trouble with it in my Sharps with the heavier bullet- this is not a load to simply use - it must be worked up to carefully, as all load data must be utilized.
: The 50/90's smaller case developed accurate ammo in less than 1/4 the time spent working on the longer case when using black powder. That's a month or two, vs. over a year with the long case. With so much powder, proper lubrication to keep the fouling soft is a major problem, bouncing back and forth between crusty fouled breech due to too hard a lube to crusty fouling at the muzzle due to lack of enough lube or too soft a lube leaving the bullet too soon in the bore. The .50/90 did not need extra lube balls to keep things soft, even with 100gr. of 2FBP for a charge - the longer case did.
: The .50/90 delivers more than enough power for any North American game & ballistics from the L:yman book can be improved upon by using AA data from their mailer handbook.
: 2.5" case- Lyman bullet- 440gr. (in their alloy)38.0gr. 5744- 1,557fps & the 550gr. RCBS w/35gr. 5744 for 1,411fps.(my preference)
: The 3-1/2" case, with 5744 runs 1978 with 440gr. and 1,736fps with 550gr. The Regular AA reloading book lists loads for both using their normal rifle powders, which is where my firend got his loads.
: Note that Federal 215 Pimers are suggested with this large bore cases.
: Hope this helps.