IMR-4831 and the 45-70?

  • Last Post 2 weeks ago
rmrix posted this 3 weeks ago

Does anyone have experience with using IMR-4831 and the 45-70?

A cast Lyman 457 193 or something in the same weight range is what I intend to make a load for. Both the Winchester 1886 and Winchester Single Shot rifles are the likely recipients.

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RicinYakima posted this 3 weeks ago

No. However I have used WWII surplus H-4831 in the trapdoors years ago. It was $1 a paper bag full and we used it like black powder that cost $2.10 a pound! Terrible!


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rmrix posted this 3 weeks ago

Yes, (H-4831) is kinda in the same league. Full, or mostly full cases.  You may not remember, but did you find some accuracy using it?

I just started testing with it, so far I can report that magnum rifle primers are a big help!

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RicinYakima posted this 3 weeks ago

IIRC, 50 grains was lightly compressed with the Lyman 457125 (500 grain) bullet. Ken Waters books have loads for the 4831 data that he said were very accurate. Ric

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BHyett posted this 3 weeks ago

My experience parallels Rick's. The benefit was cheap shots with $2.00 per pound powder, the downside was an excess of unburned powder in the barrel. Magnum primers and crimping helped that condition.

When the cheap powder was used up, I switched to Reloder #7 for light to heavy loads.


Country boy from Illinois, living in the Magical Pacific Northwest

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rmrix posted this 3 weeks ago

Yup! Those of you who responded are pretty much on it.
This is an outlier load for sure.

I have other powder choices and better powder choices but this comes with a short story. I have most of 8 pounds of this IMR-4831. The can was old enough to vote when I got custody of it and I have had it another 25 years. It was basically given to me with some other reloading stuff. That is another story. Because I have a lot of black powder rifles and only a few modern ones, and I hardly ever shoot the modern ones, there are few chances to use it up.

Last fall I cracked that eight pound can open thinking I would develop a good Win 243 Antelope load with it. …Smelled right. Looked fine. While pouring it into the hopper there was just the slightest dust, really next to nothing, but as an old handloader, I look for that kind of thing. I got the books out and made up some test loads.

I made a good hunting load and filled my tag. Hmmm. Thinking I still have most of 8 pounds of the stuff and, I would hate to let it turn into fertilizer, I remembered some old published loading data I have.
In about 1980, in the little local (to me) gun store in western Colorado, on the counter, there were IMR – loading data handouts, and I always picked this kinda stuff up. I have a bookshelf full. Why? Because I loaded, right? In the rifle cartridge section of this pamphlet, IMR listed almost all, and I mean almost all the SR and IMR powders for every round they offered data. For the 45-70 it lists load and pressure data for what I thought of as inappropriate powders like 4064, 4895, 4350, 4320 and 4831. The 4831 data showed really attractive TD or BP level pressures. That stuck with me. The down side was, who would ever spend that kind of money on loads using 50 to 56 grains of powder when you can do the same thing with ½ or even ¼ the amount of powder? Or what I guess I am really saying is, a fraction of the powder cost.

The IMR info pamphlet only listed the max powder charge and asked the reader to start by reducing it 10%. It said little else.

Well…. Here it is 2018, the powder and I are not getting any younger, and I have this 8-pound jug. And, it is going to go bad at some point.
In full disclosure, last week I made up some loads using standard LR and magnum LR primers at 50gr and 51gr and shot them, and then a few at 51.5 just because that was what the measure spit out. Lyman’s Marlin bullet (457 193) in Starline 45-70 cases was the bases of the load.
At 100 yards the Winchester single shot grouped the loads well. It did not care what the primer was. The Winchester 1886 was fussy. The 50 gr. group with the standard primer was classic, at 100y, the holes printed two inches wide and 10 inches top to bottom.
The second time out I tried the 51.5gr load, with magnum primers. This load grouped well in the Model 1886. No point trying the standard large rifle primers again. It will be all magnum primed from here on out. At 200 yards and the wind blowing, the lever rifle printed 2 inches vertical and 8 inches east and west.

I have not used the chronograph with any of the IMR-4831 loads yet. I really have not shot IMR-4831 in the 45-70 enough to really form an opinion yet. I do think there is an accuracy load here and I may not have to load it to the max to find it. And that will be fine.
BTW- the un-burnt powder issue does not seem to be very bad in this case. Only a very few yellow/brown pieces left in the barrel and none in the chamber. I was not using a crimp – I will try a few crimped too. Just because.

I have enough powder for 900 – 1000 rounds. They won’t cost me much more than the primers to make. I shoot the local NRA cowboy silhouette match a few times a year and they also have a local class for singleshot rifles too. Fun stuff. That is enough powder to keep me in that match for a while. I was not hurting for proper powder choices but I guess I will shoot this for as long as it lasts.

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RicinYakima posted this 3 weeks ago

IMR is measurably faster than the H surplus stuff. But with that said, what difference is a couple of thousand pounds at that pressure level? FWIW, the WWII stuff was pretty heavily coated with graphite to aid loading into the 20MM cases by the millions. It was notoriously dirty burning. Never noticed that unburned stick powders effected accuracy at all, compared to unburned ball powders that leave a thick goo inside the barrel.

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rmrix posted this 2 weeks ago

After testing a number of times at ranges out to 200 meters, 51.5 grs WITH Winchester Magnum primers (hot) make up the most accurate load I have shot in my Japanese 1886 Winchester!  BTW - this uses a Lyman 457-193 cast in a 4-cavity mold. Unsorted.


Just a note. As you know, all 45-70 have recoil. As loads go in this rifle, this is a very mild load. I have no idea of the velocity. At some point I will check it.


I would tell you how accurate but you would call me a lair. 


What a happy way to use up 8 lbs of old powder. I will be shooting this rifle and load in the local NRA lever silhouette match. I like shooting from my hind legs and this match is an opportunity for 40 match offhand shots in a very friendly environment. We all root for each other and cheer if ever someone gets ten in a row! 

Sorry - got carried away.

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dualsport posted this 2 weeks ago

Paul Mathews wrote about using 4831 in his book "Forty Years With the 45-70".

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Eutectic posted this 2 weeks ago

I have used many pounds of surplus 4831 in the 30.06. A full case with cast 180 grain bullets works. Accuracy and cold weather performance was improved by using Col. Harrison's recommendation of 2 grains of fast powder next to the primer. I chose Unique, but any fast pistol/shotgun powder would work, I had Unique. The Unique probably improved the velocity spread, but I did not have a chronograph back then.

This was a great load but is only attractive because 4831 was CHEAP. Now 4831 costs the same as other powders and 4895 or Reloader 7 will give the same velocity and accuracy with a lot less powder.


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