Imr sr4759

[KirkD]

It just hit me the other day that the most accurate loads for cast bullets for both my 38-55 and my 45-70 was with IMR SR4759. So yesterday, I bought a pound of that stuff with a mind to experiment with it in my 38-40, 44-40 and 32-20. Trouble is, the Hodgdon website has pretty paltry data for SR4759 in those calibers. What I'm especially interested in is the pressure data for this powder in these calibers. It is advertised as having an almost identical burn rate as IMR 4227, but my experience with my 45-70 showed that the pressure spike is definitely higher than 4227. My powder info indicates that its DPI and RQ is definitely faster than 4227 and even 2400 but slower than Blue Dot. That puts it pretty much smack dab into an almost identical pressure curve for Black Powder, somewhere between FFFg and FFg. It is an odd powder, like little doughnuts, so that it fills the case better, but it bumps up the bullet better than 2400, at least so far in my experience.

So, can anyone point me in the direction of decent load data for this particular powder? My Hornady manuals do not have much, and the Hodgdon tables seem to like faster powders for the 38-40 and 44-40.

[MakeMineA10mm]

The powder companies are nervous about people using powders that are typically best in "magnum" applications in these old rounds.

You're conclusions are very sound compared to my experience, and for what your trying to do, they shouldn't be so worried about you "magnumizing," since you're just wanting optimum cast-boolit loads...

I checked my old Lyman #44 manual. No luck.
Checked an older IMR guide/pamphlet. Same.
Checked the newest Hodgdon Annual Manual (with IMR data in it). No joy.

I think you're going to need someone who has a recent IMR guide (but from before their distribution/sales/loading guide was taken over by Hodgdon), so that it has Cowboy data in it, and see if they list any. They still might not, because of the liability worry over someone magnumizing the old cartridges...

Worst case scenario, you could use some Blue Dot/800-X starting loads and work up from there until you get efficient burning with suitable velocities. If you can't get that combination, maybe it's just not a good powder for these rounds.

[ktw]

Ken Waters Pet Loads has some 38/40 and 44/40 SR4759 loads.
Lyman 42 also lists SR4759 loads in both cartridges.

14-18gr appears to the charge range of choice in both manuals (180 gr boolit in 38/40, 200gr in 44/40)

-ktw

[JSH]

It just hit me the other day that the most accurate loads for cast bullets for both my 38-55 and my 45-70 was with IMR SR4759. So yesterday, I bought a pound of that stuff with a mind to experiment with it in my 38-40, 44-40 and 32-20. Trouble is, the Hodgdon website has pretty paltry data for SR4759 in those calibers. What I'm especially interested in is the pressure data for this powder in these calibers. It is advertised as having an almost identical burn rate as IMR 4227, but my experience with my 45-70 showed that the pressure spike is definitely higher than 4227. My powder info indicates that its DPI and RQ is definitely faster than 4227 and even 2400 but slower than Blue Dot. That puts it pretty much smack dab into an almost identical pressure curve for Black Powder, somewhere between FFFg and FFg. It is an odd powder, like little doughnuts, so that it fills the case better, but it bumps up the bullet better than 2400, at least so far in my experience.

So, can anyone point me in the direction of decent load data for this particular powder? My Hornady manuals do not have much, and the Hodgdon tables seem to like faster powders for the 38-40 and 44-40.


You start off speaking of SR 4759, then mention it is shaped like little donuts. SR4759 is a big stick powder the last 100 pounds I loaded up?
Trail Boss is shapped like donuts, little round disk with a hole in the center.
If you email or call Hodgdon's, they will give you a start load for about anything it has applications in.
Jeff

[KirkD]

JSH, I was mistaken .... it is a stick powder, but with a hole that runs down the center, like a thick-walled tube. I just checked the batch I purchased. It has been a while since I tried it out and I recalled the hole, but not the shape.

MakeMine, I was thinking of using Blue Dot data as a safe approximation of 4759 loads, but I think I finally have to break down and get my own copy of Ken Waters' Pet Loads.

KTW, thanks for that info. Overall, I'm looking for original Winchester velocities. I stay away from the steamier loads.