Well, after four months of no serious shooting, I figured it was time to get to the range and try out a new powder. I've been very interested in IMR SR4759 for the reason that it seems to give a pressure curve very close to black powder. Here's a report on the results of my first two loads, which turned out to be a bit conservative.
Rifle: Winchester Model 1892, made in 1913
Caliber: 38 W.C.F., also known as the 38-40
Original Black powder ballistics from 1896 Winchester catalogue: 180 grain pure lead bullet @ 1,268 fps
Load #1: 15 grains of IMR SR4759 under a 180 grain RCBS FN PB bullet sized to .401
Load #2: 17 grains of IMR SR4759 under a 180 grain RCBS FN PB bullet sized to .401
Chrono results of Load #1: 974 fps with an E.S. of 27 fps and an S.D. of 12 fps (5-shot reading)
Chrono results of Load #2: 1,094 fps with an E.S. of 105 fps and an S.D. of 35 fps (10-shot reading)
Here's a photo of my old 96-year old 38-40 ....
First off, I tapped the rear sight over a tad, since previous trips to the range showed that it was hitting a bit to the left. To see if I'd adjusted properly, I set up a target at 50 yards and I fired off two rounds that had not been neck sized at all. The bullets were loose in the neck and held in by the crimp. I didn't want to use these in my official test, so I used them as sighters. The two bullets were very close to dead center laterally so I set up a target at 100 yards. Interestingly, the two bullets that were loose in the necks gave me exactly 100 fps more velocity than the same 15 grain load did when I sized the neck halfway down to the shoulder.
Load #1 Results at 100 yards:
First off, I was amazed at how slow the velocity was. Ken Waters lists 1,153 fps for the same load. Mine putted along at a sedate 974 fps. The rear notch is a small notch within a larger notch, making the top shoulders of the sighting notch not well defined. As a result, my vertical hold was a bit dicey. After 8 rounds fired into the 100 yard target, I had a horizontal spread of only 1 & 1/2", but a vertical spread of a whopping 4 & 1/4". I'm sure it was the problem of the poorly defined shoulders in the rear sight notch. I will have to do some work on that notch. Anyway, here is a photo of the target .....
Load #2 Results at 100 yards, 5 minutes cooling after first 2 shots:
I tried a lot harder to obtain some sort of consistency with my vertical hold on the rear sight notch. After two shots, I headed down range to take a look. It was encouraging, so I went back and fired off the remaining three rounds for this set. Again, I was surprised at the low velocity I got compared to Ken Waters for the same load. He got 1,339 fps and I only got a measly 1,094 fps. The necks were still sooty, so I'm definitely not getting a very high pressure with this load. I got a decent 5-shot group of 2 & 3/8" (100 yards with open iron sights). Still possibly a bit of vertical spread, but I was pleased. Here's a photo of the target ....
Load #2 Results at 100 yards, 5 fairly quick shots, no cooling:
Finally, I decided to crank out 5 shots in a row with no cooling, but still with reasonably careful aiming. This group was not too bad, 5 shots forming a 2 & 7/8" group at 100 yards, but it was spread a bit more horizontally. I wonder if it was from a warming barrel. Here's a photo of that target .....
Concluding thoughts:
Ken Waters lists the max load for Group two rifles as 19 grains of IMR SR4759. I don't know if his batch of 4759 was different from mine, but I do know that his batch would have been a sight older than mine, just bought this past month. I really want to develop a hunting load of around 1,500 fps. Next loads will be 18 and 19 grains of SR 4759. If I can't get 1,500 fps with the 19 grain load, I may have to go with 2400. I see I still have to tap that dadgummed rear sight over a wee bit more.
Rifle: Winchester Model 1892, made in 1913
Caliber: 38 W.C.F., also known as the 38-40
Original Black powder ballistics from 1896 Winchester catalogue: 180 grain pure lead bullet @ 1,268 fps
Load #1: 15 grains of IMR SR4759 under a 180 grain RCBS FN PB bullet sized to .401
Load #2: 17 grains of IMR SR4759 under a 180 grain RCBS FN PB bullet sized to .401
Chrono results of Load #1: 974 fps with an E.S. of 27 fps and an S.D. of 12 fps (5-shot reading)
Chrono results of Load #2: 1,094 fps with an E.S. of 105 fps and an S.D. of 35 fps (10-shot reading)
Here's a photo of my old 96-year old 38-40 ....
First off, I tapped the rear sight over a tad, since previous trips to the range showed that it was hitting a bit to the left. To see if I'd adjusted properly, I set up a target at 50 yards and I fired off two rounds that had not been neck sized at all. The bullets were loose in the neck and held in by the crimp. I didn't want to use these in my official test, so I used them as sighters. The two bullets were very close to dead center laterally so I set up a target at 100 yards. Interestingly, the two bullets that were loose in the necks gave me exactly 100 fps more velocity than the same 15 grain load did when I sized the neck halfway down to the shoulder.
Load #1 Results at 100 yards:
First off, I was amazed at how slow the velocity was. Ken Waters lists 1,153 fps for the same load. Mine putted along at a sedate 974 fps. The rear notch is a small notch within a larger notch, making the top shoulders of the sighting notch not well defined. As a result, my vertical hold was a bit dicey. After 8 rounds fired into the 100 yard target, I had a horizontal spread of only 1 & 1/2", but a vertical spread of a whopping 4 & 1/4". I'm sure it was the problem of the poorly defined shoulders in the rear sight notch. I will have to do some work on that notch. Anyway, here is a photo of the target .....
Load #2 Results at 100 yards, 5 minutes cooling after first 2 shots:
I tried a lot harder to obtain some sort of consistency with my vertical hold on the rear sight notch. After two shots, I headed down range to take a look. It was encouraging, so I went back and fired off the remaining three rounds for this set. Again, I was surprised at the low velocity I got compared to Ken Waters for the same load. He got 1,339 fps and I only got a measly 1,094 fps. The necks were still sooty, so I'm definitely not getting a very high pressure with this load. I got a decent 5-shot group of 2 & 3/8" (100 yards with open iron sights). Still possibly a bit of vertical spread, but I was pleased. Here's a photo of the target ....
Load #2 Results at 100 yards, 5 fairly quick shots, no cooling:
Finally, I decided to crank out 5 shots in a row with no cooling, but still with reasonably careful aiming. This group was not too bad, 5 shots forming a 2 & 7/8" group at 100 yards, but it was spread a bit more horizontally. I wonder if it was from a warming barrel. Here's a photo of that target .....
Concluding thoughts:
Ken Waters lists the max load for Group two rifles as 19 grains of IMR SR4759. I don't know if his batch of 4759 was different from mine, but I do know that his batch would have been a sight older than mine, just bought this past month. I really want to develop a hunting load of around 1,500 fps. Next loads will be 18 and 19 grains of SR 4759. If I can't get 1,500 fps with the 19 grain load, I may have to go with 2400. I see I still have to tap that dadgummed rear sight over a wee bit more.
