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Lindenwood 08-14-2011 04:15 PM

.45-70 and Unique, how hot can I load it?
Does anyone have or know where I can find load data for .45-70 and Unique powder using a 300gr bullet? I just want to know how far one can go with it. I've been searching for the last hour or so and have found a few bits here and there that suggest ~18-20gr of Unique under a 300gr bullet should give maybe 1800fps or so and maybe 30k PSI, but I'd like something a little more concrete than that.


JonM 08-14-2011 05:14 PM

unique is a fast buning pistol powder and its exceedingly dangerous to use in long barreled rifles. the loads your finding are for pistols like the tc contender and other such very short barreled firearms.

using those loads in a rifle barrel will increase the pressure substantially and lead to a kaboom killing or injuring you and nearby folks.

dont do it.

Lindenwood 08-14-2011 06:26 PM

I know the Lyman books list these types of loads, but I don't have any of them and was just looking for some rough information before I got into it. Longer barrels don't increase pressure, as peak pressure occurs in the first couple inches of bullet travel. In any case, I know it is actually pretty common for people to shoot these types of reduced loads in .45-70 rifles, sometimes just for reduced-recoil plinking and at other times to replicate original black powder specs. However, they usually don't push the loads that fast, and most people seem to use much heavier bullets. But I've found loads showing, off the top of my head, something like 16gr of powder giving maybe 1400fps with a 400gr bullet, with a peak pressure of 26k PSI. BTW, technically Unique was originally marketed as a reduced-load rifle powder.

I only ask because I've been considering getting a lever action and was just curious how versatile it could be using Unique as the primary powder. The ability to push a 300gr bullet to maybe 1800fps would match a lot of factory loads and would be a good moderate load for potential defense or bench shooting, but the reduction in powder would save about $5 per 50 rounds. Of course, if I really wanted to hotrod I would naturally use more traditional powders, but Im just curious how far one can go with Unique.

JonM 08-14-2011 09:49 PM

thats not true of pistol powders. they are very fast burning design to peak rapidly and drop the pressure when the bullet leaves the barrel. 20grains is a LOT of powder for unique in a very large case. you have a much longer sustained pressure curve that starts rapidly and stays there. 45-70 cases arent all that strong and the case is normally the fail point.

you can do what ya want, just be sure your using an inert case filler to take up some of the empty space.

i personally dont see the point of doing something risky like that.

but you got my opinion. maybe someone else has a different one.

lonewolf101 08-14-2011 10:47 PM

This is nout of the LYMAN MANUAL 45/70 for win 1886&marlin 300 gr.bullet dosent list that powder but list mine! varget 57.0grains what other powder you have?

Lindenwood 08-15-2011 01:05 AM

At the moment I only use Unique but was thinking about picking up an 1895 in .45-70 and was just wondering what could be done with it. Most of my research says fillers arent necessary or recommended with Unique.

But, for example, this site has lots of load data and is showing 14gr of Unique under a 405gr bullet for about 1170fps, which might translate to about 1300fps or so with a 300gr bullet.
45-70 Government Powder Weight /Velocity Data for the 405gr FPbb

Here is a thread with a lot of good information about reduced loads.
UNIQUE powder for 45-70 target loads?


the 1970 Lyman-44th edition lists unique 14 to 17 gr w/ the 385 gr cast, 13 to 16 gr with th 482 gr bullet, and 12 to 14 with the 552 gr.
The 17gr loading with a 385gr bullet is one bit of information from which I derived the 18+ with a 300gr bullet. I don't know the specific pressure on that load, though, but I haven't found any specifying peak pressures over 26k PSI. Of course, I'd look more specifically into it (get some manuals, etc) before I ever loaded anything up, but I'm just looking for some rough info. And, of course, I would still keep the denser rifle powder(s) around for the time I really want to hot-rod, but I'd imagine most loads on a given range trp would be filled with Unique rather than those rifle powders, especially if ~1800fps is possible with a 300gr bullet. I have some .30-06 loads saved somewhere that I believe show a max loading of Unique (25gr) under a 150gr bullet gives somewhere around 2400fps, compared to about 2900-3000 with a rifle powder and max load. Of course, I wouldn't want to push it that hard and, for example, would have settled for 2200-2300 if I were going for general plinking loads. But, it does show that one can get pretty decent performance with the moderately-fast powders like Unique, and if a max load of rifle powder will push a 300gr bullet to 2400fps, I don't think 1800fps at the same pressure with Unique would at all be out of the question.

robocop10mm 08-15-2011 02:27 AM

I have been reloading for 30+ years. The only time I have done something disasterous was using Unique for reduced loads in .223. I blew up a Mini-14. It is very easy to double charge with Unique or any other pistol powder in a large capacity case like the 45-70.

I understand the allure of limiting the inventory of powders, but there are limits. The fastest powder I would consider in the 45-70 is IMR-4227. It fills over 1/2 of the case capacity (in all reasonable loads) so is pretty much impossible to double charge.

I only keep 5 powders on hand and I load almost everything from .32 ACP to .454 Casull and .223 to 45-70.

lonewolf101 08-15-2011 12:05 PM

These are all the powders for the 45/70 with the 300 grain bullet.

imr 4064
h 4895
h 322
imr 3031 xmr 2015
n 130
imr 4198
xmp 5744


Lindenwood 08-15-2011 02:27 PM

I always do...


the 1970 Lyman-44th edition lists unique 14 to 17 gr w/ the 385 gr cast, 13 to 16 gr with th 482 gr bullet, and 12 to 14 with the 552 gr.
And this is a very nice article summing up 80k rounds worth of research done on "pistol" powders in rifle cartridges:

It's not like I'm pulling this idea out of thin air, heh.


And Robo, that is definitely true and is a very valid concern with any reduced load!

quigleysharps4570 08-16-2011 02:35 PM

The Lyman Cast Bullet handbook has several loads using Unique powder. It shows loads for all 3 actions too...1873 Springfield, the lever guns and the Ruger #1. If you are interested I will scan them and post them. ;)

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