I like the bulk of IMR SR4759 for filling up the case a bit better than other medium speed powders such as 5744 (which I use a lot). I figured I'd develop a good, accurate load for SR4759 that had a similar velocity to the original Winchester cartridges in the 1890's (1,286 fps fifty feet from the muzzle, or 1,320 fps near the muzzle).
Rifle: Winchester 1886
Caliber: 45-70
Barrel: Octagon
Trigger: plain
Date in: July 1, 1890
Shipped: August 4, 1890
Sights: An original Lyman tang sight, here's a photo ....
First Trial Load:
26 grains of IMR SR4759 and a Wincheter Magnum Rifle Primer under a 405 grain plain base cast bullet. I tried two, five-shot groups at 100 yards. Here are the results ....
The slightly lower velocity looked a wee bit looser and, overall, the two groups were not as tight as I was getting with 5744 at a slightly higher velocity, so I decided to boost the load by a half grain and see what happened.
Second Trial Load:
26.5 grains of SR4759 with a Winchester Magnum Rifle primer under a 405 grain plain base cast bullet for 1,378 fps and an extreme spread in velocity of 37 fps. (9 shots). The first and last shots were called flyers, both slightly high and to the left of where I should have been aiming. Unfortunately, I do not know which holes those represent. I'd like to believe they are the two at the top left corner of the group, but I do not know. Still, the group demonstrates what I would call a good, accurate load. It is slightly faster than the original 1,320 fps, but still below 19,000 CUP. Here is the target ....
Rifle: Winchester 1886
Caliber: 45-70
Barrel: Octagon
Trigger: plain
Date in: July 1, 1890
Shipped: August 4, 1890
Sights: An original Lyman tang sight, here's a photo ....
First Trial Load:
26 grains of IMR SR4759 and a Wincheter Magnum Rifle Primer under a 405 grain plain base cast bullet. I tried two, five-shot groups at 100 yards. Here are the results ....
The slightly lower velocity looked a wee bit looser and, overall, the two groups were not as tight as I was getting with 5744 at a slightly higher velocity, so I decided to boost the load by a half grain and see what happened.
Second Trial Load:
26.5 grains of SR4759 with a Winchester Magnum Rifle primer under a 405 grain plain base cast bullet for 1,378 fps and an extreme spread in velocity of 37 fps. (9 shots). The first and last shots were called flyers, both slightly high and to the left of where I should have been aiming. Unfortunately, I do not know which holes those represent. I'd like to believe they are the two at the top left corner of the group, but I do not know. Still, the group demonstrates what I would call a good, accurate load. It is slightly faster than the original 1,320 fps, but still below 19,000 CUP. Here is the target ....
