IMR4198 in the 1876 Uberti

[cat1870]

Has anyone had any luck using IMR4198 in the .45-60 with 300 grain cast bullets?

[OKDEE]

Hey cat,  I do not have a 45-60, but I do have a 45-75 Chaparral.  I tried the IMR 4198 powder and found it to be inconsistent for the 350gr and 325gr bullets, in my rifle.  For my rifle, the IMR 3031 seemed to have the best fit.

Oklahoma Dee

[Trailrider]

Howdy, Pard,

As you may know "the other website" prohibits publication of loads (even the mention of the original factory/military loads will get your entry edited out or banned!).  If you understand that the undersigned CANNOT BE RESPONSIBLE FOR THE USE OF THE FOLLOWING DATA in either original OR REPLICA M1876 rifles, I would quote an article published in the July-August 1973 issue of Handloader magazine, a Lyman 457191, 292 gr (Lyman #2 alloy) backed by a charge of 25.0 gr IMR4198 plus a 1/4 square of single-ply Scott's toilet paper poked LOOSELY into the case and "compressed" by the bullet yielded 1237 ft/sec from an original M1876 with 28" bbl.  Cases were Winchester .45-70 cut to length and the rims needed to be thinned slightly.

Another article, published in an unknown magazine, possibly Handloader, showed a 325 gr cast bullet with a 26 gr charge but NO filler, at 1297 ft/sec.

At the time these loads were published there was no practicable means available to test pressures, and I doubt the shooter would have been willing to mess up the finish of an antique arm by cementing the strain gage of an Oehler M43 Personal Ballistics Lab to the barrel even if the test equipment had been available!

At this point I CAN NOT actually recommend such loads, although they seemed mild enough according to the authors.  The question is what is the rate of increase of the pressure-time curve compared to BP loads.  Similar tests with .45-70-300 and slightly hotter loads of IMR4198 + the T.P. wad, using the M43 equipment on a strong rifle, and comparing the loads with Remington .45-70 factory loads appeared similar, though NOT IDENTICAL in terms of the shape of the pressure-time curves as well as the maximum pressures yielded.

BUT, SINCE THE BASIC TOGGLE LINK ACTION IS STILL CONSIDERED A WEAK ONE, YOU USE SMOKELESS POWDERS AT YOUR OWN RISK!

I would have to agree that perhaps IMR3031 might be a better choice, due the slower burning rate.  I don't have any recommendations other than to use proportionally LESS of that powder than the data shown for 292 gr #457191 in the Lyman manuals for the Trapdoor Springfield.  In other words, you measure the water capacities of the .45-70 and .45-60 brasses with the bullets seated.  BUT, AGAIN, I ASSUME NO RESPONSIBILITY FOR THE USE OF SUCH DATA!

Ride CAREFUL, Pard!

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[Harve Curry]

Look here for researched data about smokeless powder in volumous cases, and at the 45-70 load data:

http://www.gmdr.com/lever/lowveldata.htm

It has been being done for well over 100 years. You can reload efficient smokeless loads well within the pressure limits of your rifle, velocity from 1000fps to 1500' FPS MV, and be easier on your rifle. A wealth of info is in the book called " Forty Years with the 45-70", alot can be interpolated to the 45-75 and also the 45-60. Generally rifle powders need to burn at higher pressure so I would stay clear of them for reloads of 10,000psi to 25,0000psi range.