Morning, I’m just about to start with my new Miruko ‘86 in 45/90. I had a Pedersoli Sharps before but only shot black in it. I want to work up loads that are not crazy but above 45/70 with smokeless. Planning on full case with whatever powder works best. Anyone else doing this? Oh, I’ve been loading for 40 years so I don’t need negative input. Thanks
Full power 45/90 loads?
- Thread starter MTM
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I have some smokeless 45/90 loads listed in my 1957 Lyman 41st. Handbook for 300, 345 and 400gr. cast, plus 300 and 405gr. jacketed bullets.
Never tried them myself as I used to use black-powder only in my old 45/7s and 45/90
If you p/m me your email address I'll scan and send them to you.
Never tried them myself as I used to use black-powder only in my old 45/7s and 45/90
If you p/m me your email address I'll scan and send them to you.
I have a 45-90 and a 458 Win Mag, which have the same bore diameter and very close case capacities, the 458 Win Mag being about 4% greater in capacity, hence a load in one will produce very similar results in the other.
It's up to you to know the strength of your gun, but Hodgdon has quite a few loads for the 458 Win Mag and lists pressure for them.
Using H4198 and a 400 gr bullet as an example, in the 458 Win Mag, the start load of 61.0 grs produces 44K CUP and 67.0 grs produces 51K CUP, while in the smaller capacity 45-70, 53.0 grs produces 49K CUP. Essentially 53.0 grs in the 45-70 produces only slightly less pressure than 67.0 grs does in the 458 Win Mag.
What I'm trying to say is that you can use 458 Win Mag loads in the 45-90 assuming that the rifle being used is of sufficient strength, and I recommend going no higher than using 458 Win Mag Start Loads as 45-90 Max Loads.
It's up to you to know the strength of your gun, but Hodgdon has quite a few loads for the 458 Win Mag and lists pressure for them.
Using H4198 and a 400 gr bullet as an example, in the 458 Win Mag, the start load of 61.0 grs produces 44K CUP and 67.0 grs produces 51K CUP, while in the smaller capacity 45-70, 53.0 grs produces 49K CUP. Essentially 53.0 grs in the 45-70 produces only slightly less pressure than 67.0 grs does in the 458 Win Mag.
What I'm trying to say is that you can use 458 Win Mag loads in the 45-90 assuming that the rifle being used is of sufficient strength, and I recommend going no higher than using 458 Win Mag Start Loads as 45-90 Max Loads.
Buyers remorse...NO! You have a fine rifle. The basic M86 action is length limited to about 2.8" OAL. The 45-90 in the M86 was designed as what's called an "Express" cartridge/rifle. That simply means designed to shoot somewhat smaller bullets faster. Since the basic J Browning M86 design has that length limitation of about 2.8" it was used primarily for the 45-70 and with bullets ranging from around 330 gr. all the way up to 500 gr. with a rifling twist rate of about 1:20". But for marketing reasons in a very competitive market, Winchester decided to take the basic 45-70 case length of 2.1" and extend it to the practical limit for the M86. (Winchester also designed an even more hot roddy cartridge for the M86, considering the era, the 33WCF.) The limit for the 45-70 family in 45 cal seemed to be the 45-90 (45 2.4). Which allowed for a much more "modern" type load that used a smaller bullet at a measurably higher muzzle velocity (Express). The down side trade off was (is) the big long bullets loaded in the 45-90 case take up so much powder space they begin to approach 45-70 ballistics. When Winchester designed the 45-90 they also decided to use a slower rifling twist rate of about 1:32. That is better for the smaller (shorter) and faster 45 cal bullets in the 300-350 gr range. But is usually not a fast enough twist for best stabilization the heavier 400-500 gr bullets.
So, the 45-90 in the M86 is a fine performer in the context of its purpose as an Express type rifle/cartridge. One thing you might do is to check the twist rate of yours. I don't know what twist specs Miroku used for the M86 in 45-90. If it is faster than the original rate of 1:32" then you can expect good results with bullets clear up to 400 +/- gr. And, if in the 1:20" range then it will stabilize bullets up to about 500 gr. but as covered earlier, with the heavier bullets, it will have ballistics basically the same as the 45-70. Hope that helps
So, the 45-90 in the M86 is a fine performer in the context of its purpose as an Express type rifle/cartridge. One thing you might do is to check the twist rate of yours. I don't know what twist specs Miroku used for the M86 in 45-90. If it is faster than the original rate of 1:32" then you can expect good results with bullets clear up to 400 +/- gr. And, if in the 1:20" range then it will stabilize bullets up to about 500 gr. but as covered earlier, with the heavier bullets, it will have ballistics basically the same as the 45-70. Hope that helps
