The Bell brass is the same as the Brass Extrusion, James is the son of Jim Bell of Bells Gunshop in Highland Park, Ill. Good folks and good brass.

Question: what is the seating depth of your bullets, most just barely seat the patched bullet in the case so that the bullet is in the riflings for better alignment and properly obutrated(sp) at firing.

Drop Beltfed Arnie a message, he has plenty of experience with black powder and is willing to share his  considerable knowledge. Good luck.

I think you’ll find you’re going about the paper patching process the hard and no so accurate way when compared to the dual diameter bore rider approach. Obturation is your friend when using black powder and the further the bullet is in the bore the better it shoots. Beltfed Arnie uses this method and explains it much better than my abilities. A study of Shiloh Sharps forum will also get you on the right path as well as a visit to a local BPCR match.

Ok, this is just my opinion and most can be proven wrong in certain circles. The number 50-90 is attached to a 2 1/2 case length but is also referred to as a 50-90, 50-100, and 50-110, all on the same length cartridge case. The difference in the loads is the bullet weight which also relayed to a different seating depth of the bullet’s base; the lighter the bullet the less length there is and also the a longer powder column relating to a larger charge of powder; all are no air space charges. 

Loading a charge involves first establishing the bullet seating depth which also sets the compression height at the same time when the wads are also in the measurements. Once the compression height is known it is from there the amount of powder is placed in the case and the volume/weight is determined. Adding more powder from the initial charge requires more compression limited by the amount of case expansion due to the forces on the case walls. 

The number assigned to the case back in the day means nothing to loading a modern case or for that matter a load back in the day. Just a best estimate at best. Today top shooters load charges to the half grain, maybe less, so the number is whatever your rifle likes. 

All said, black powder is too easy to load in cartridges and most of us try using smokeless powder methods and knowledge which only confuse the process.

From what I've read the .50-140 3.25" was loaded with either 678 gr. bullets, or as more of an "express" load with a 500 gr. bullet. 
That's what makes me wonder why a load of 1.5fg powder is so much lighter than the "140 gr." the case is represented as. I don't compress much at all with my .45-70 and I can easily get 68 grs. with modern brass and a 535 gr. bullet. I don't often load them that heavy as over a match length the recoil isn't really comfortable in my 10.5 lb. rifle.
I'm not looking for more powder in my .50-140 cases, as even my 15.25 lb. Sharps can get somewhat heavy recoil. Just was curious about the 20 gr. difference in the capacity. I may even consider dropping down to 1fg BP later, just to see if it makes any difference in recoil or accuracy.

The Swiss powder in the blue-label bottles was dense enough to get 80 gr of Fg into a fireformed .45-70 case by trickling through a droptube.  This left enough room for a 1/16” cork wad to be just short of flush with the case mouth, and then I’d compress the column ~1/8” below the mouth, seat a paper patched bullet and slightly reduce the mouth to hold the cartridge together.

When Olde Eynsford first came out, I couldn’t get 80 gr of Fg into the case, so I stuck with the Swiss.  But then Swiss came out with the pink-label bottles and the contents were less dense than the old blue-label Swiss.  80 gr 1 Fg would overflow a fired case, even when droptubed.

Recent purchases of Olde Eynsford 1-1/2Fg seem to be slightly more dense than earlier purchases, and, if anything are more dense than the current Swiss powder.  I’m currently scrambling to get a load with my remaining stock of OE that’s as good as the original Swiss.  I’m sure when (or if) Estes starts making OE again, there’ll be another density difference to cope with.

I don’t subscribe to this “Black by Volume” business.  It’s fine if the density is the same (or you’re “barking squirrels” at 30 yards with “Old Betsy”), but for BPCR at mid- to long ranges, that isn’t the case, if it ever was.  Energy is converted from mass, which is derived by weight.  It may be dispensed by volume, like gasoline, but people do notice a slight increase in “mpg” when they fill their tanks on a cold day vs. a hot one.  That’s because the fuel mileage comes from the weight burned.

Your paper patched bullets should push through the bore with a stout cleaning rod.  If not, somebody set up for “patch to groove” bullets, which have to be seated deep like grease-groove bullets.  If the previous owner was using smokeless powder, that would be the only way to make paper patch bullets work.  The dual-diameter bullets enable them to be barely seated into fired cases from grease-groove chambers without needing a squish in the mouth reducer die afterwards, with most of the bullet still projecting out into the bore, but they still need the particulates in the black powder deflagration to slug or rivet them fully up to groove diameter.

For someone new to BPCR, the .50-140 is certainly in the postgraduate area for learning the ins and outs of paper patching.  A friend quit using his at the Quigley, finally admitting it was never accurate enough. I recall his load was 138 gr of 1Fg Swiss with a 600-gr patched-to-bore bullet.

Marlinguy, not to run this thread off it’s track but once you come to terms with your best loads you will then have to figure out the best way to control the fouling and the 50-140 is a case study in itself. Without fouling control in your shooting process you will not find a good load. Good luck on your endeavors.

1 f will be your friend in that 3 1/4 case. If you can handle the recoil and not get the flinches or jumping the trigger anticipating the recoil, it should be as accurate as any other rifle once the right load is found.
But the few that do/did shoot the 50-90 in competition have given up on it due to the punishing recoil, and having shot a 3 1/4 a bit, it's a one or 3 shot deal.... maybe good for hunting, but just to much of a good thing for competition.