March 21, 2011
I have loaded 10 rounds of 45-75 WCF that I made from 50-90 Sharps. I cut the sharps 50-90 cases down by 1/2″ then I turned the rims down from .562″ to .527-.528″, from there I ran them through a RCBS die set for the 45-75 WCF to form them into the new caliber. I trimmed them to 1.890″ in length and then ran them through my tumbler overnight before I annealed them twice in my AMP annealer. I had some 350gr copper jacketed lead bullets made by Hawks bullets made. I received the bullets last week and loaded up the 10 rounds with 42gr of Blackhorn 209 powder, F215M primer, seated to base of neck. .360″ of .900″ long bullet protrudes from case making it 2.250-2.260″. They run great through the magazine tube, cycle through the chamber, and eject just fine. Since I cannot find any good load info I went off what the 45-70 was loaded with using the same brand of powder, I backed down from that and I will test fire these this weekend up in the hills. I won’t be holding the rifle when I do (no idea what the pressure will be). I will attach a Magnetospeed chronograph to measure velocity at the muzzle, but I have nothing to measure pressure. I plan to be about 30-50′ back and pull the trigger using a string. I am expecting the velocity to be in the 1350-1450FPS range. Anyone have something to add to this or concerns? I will try and remember to show results after Saturday when I get home. Good or Bad. This is the first round I ever loaded where I had to make the entire bullet and shell and load without any load recipe. I could use BP and I might still do that, I definitly don’t want to use smokeless powder.
I’m just checking but I think you missed your rim diameter by a tenth as mine measure .626″. I also have JBA headstamped that measures .6155″. All your other specs match my cases & OAL.
June 11, 2014
I recently acquired 20 brass cases from Ammunition Artifacts. It was the last bag they had for “original” spec cases with thinner rims. They formed it from 3 gauge brass. I compared the volume with an original, ballon-head case from back in the day and they seem to hold the same volume, around 81 grains of water. The chamber perfectly in my original ’76 NWMP carbine, but with a .458 bullet installed will not fit. Turns out the neck wall thickness is .014 when it should be 8 to 10 thousands of an inch. I have a steel jig that tightly fits into the neck and then into a drill, so I have to sand down the outside of the neck by .004″. I’ve got dies and a custom bullet mould coming from Accurate Molds. Original velocity was 1,380 fps measured 50 feet downrange, from a rifle. Muzzle velocity was closer to 1,430 fps from a rifle. From a 22″ carbine barrel, muzzle velocity would probably have been closer to 1,380 fps. I’ll be using 5744. I’ll start with my 5744 load for the 45-60, choreograph that to see how close I come to original ballistics and adjust.
With a case close to original volume, and a lead bullet cast to original weight, and at original ballistics, 5744 will give a lower peak pressure than BP.
The rounds I made and loaded with 42grs of Blackhorn 209 powder filled the case to the base of neck, I doubt that 17.5grs of any powder would fill a 45-75 WCF case. I am not familiar with that powder as I have never used it, but I have loaded 357 mag cases with Winchester 296. I think I used 16grs in my load, that is a much smaller case than the 45-75 for sure by twice the size. My rifle is not an original either so I am able to load it a bit higher than everything I have read when loading for an original 1876 Winchester. As I stated in my first post, I would never start any higher than 35-37grs of the powder that I used in this load.
Chuck, When I called Hodgdon and explained what I was doing and my load, all they recommended was to add a cardboard wad behind the bullet.
Again my load was for a reproduction not an original.
50-90 Sharps (Starline case) converted to 45-75 WCF brass 1.895″ after fire formed was 1.890″
Blackhorn 209 powder 42gr
Federal 215M primer
Hawks Bullets 350gr X .035″ copper jacket (bullet is .900-.903″ long) cannelure set back .360″ from nose.
bullet seated .540-.543″ into case for overall length 2.250″- 2.260″
no fills and no gaps between powder, wad, & bullet.
first 10 rounds shot data are displayed in previous post above. I did anneal all cases twice in a AMP annealer setup. I sent samples to Alex in
Australia. His annealing settings are under the “Standard settings” only. I have loaded up another 60 rounds and will use these to get the rifle dialed
as accurate as my old eyes can do. This should give anyone at least some idea where to start with their loads. Original Winchesters should most likely
start 5-7 grains of Blackhorn 209 less than what I did. I was shooting for a MV of between 1300fps and 1450fps, my load above did just that. I believe
the originals were loaded for 1350-1380fps if I remember reading correctly. Good luck….
October 4, 2011
Interesting reading. My 76 is an early Uberti with the so-called Uberti chamber. So far is seems to favor IMR 4198, Trail Boss, and Shooters World Buffalo Rifle powder. I have a few hundred Jamison 45/75 pieces, got them when the getting was good. Been shooting Laser Cast 350 FN bullets, as that’s what I got for my 45/70’s. I have a couple boxed loaded with Swiss and Goex, but haven’t shot them yet. And now have a tang sight of unknown origin mounted. It appears to be very well made. I had issues with the main spring falling off, but I believe thats been fixed. Hope to get out soon to shoot those BP loads.
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