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[Tundra Tiger]

I had to go back to see I was the person who started this thread.

My goal is a modern (Miroku?) rifle and modern loads - something that shoots at 4000 ft pds+, and there is ammo available that achieves that.

 

[fourfive8]

OP’s question- easy answer. Get a Lyman 48th Edition (or newer) Reloading Handbook. Two examples of “pictures for bigger words” attached.

 

[Daryl S]

One way would be to buy a box of THAT ammo and take one or two apart and try to identify the powder & weigh it.
Aside from that, start with max loads for a Marlin lever gun in .45/70, go from there, if pressure signs indicate you can. You will not find the data you seek from any powder company or a loading manual, unless you can find an old AA(Accurate Arms) manual with the red covers. They had the data you are looking for. The top loads for a Marlin .45/70 or .458 Marlin are likely 40,000psi to not over 43,000psi. This 43,000psi is the maximum suggested for the Marlins. The 86 WILL 'take" a bit more. These cases are immensely strong in the head area due to the rim diameter(mostly). Marlin noted some time ago, they loaded a case to 70,000psi and had no problems with the rifle or the case. 70,000 is not loading data, but they did that to show what the rifle with it's small barrel diameter and the ctg. would 'stand'.

 

[Daryl S]

I forgot I had a #51 Lyman book. It lists cast bullet loads for .45/90 in Modern Guns designed for Smokeless powder.
The velocities shown are higher than data for modern Lever Gun .45/70 loads.
385gr. @ 2,134fps
400gr. @ 1,948fps
500gr. @ 1,772fps
535gr. @ 1,707fps
These are the highest vel. posted for these cast bullets.

 

[Don458]

1960 Lyman vol 42 has some general loads. But seems like you’re looking for power load. Let me know if you want the load data.

 

[Rafiki]

I've had my 45-90 Rollingblock shooting 500gr Interlocks at over 2000fps. Shot clear through a bison; way too much power.

 

[Daryl S]

Must have been a Navy Arms #1. Had one of those, with a tight Hoch (.456").458 barrel & chambered for the .45 3 1/4". I shot it only with black powder, but has been said in one or more gun rag. magazines that it was an enormously strong action & capable of handling 50,000PSI loads. I would not have attempted that regardless of what was printed.
I did 2,050fps in both of my .458 2" Mausers, a VZ 34 and a Mark 10 with 500gr. Hornady RN's & in the first one, with Winchester 510gr. as well.

 

[mgstucson]

I really hope you find your load and keep us informed. I wanted to go that way and get a 500gr bullet to 2100fps, but I was afraid it was impossible to obtain if I stayed with COL of the standard 45-90, and under 50,000psi which some say is the limit for the modern steel 1886.

I started building a long throated 45-100 double instead.

You might find this info helpful.

45-90 Tale of 2 rifles

 

[Daryl S]

Lyman #51 also has data for the .45 2.6", .45 2 7/8's and .45 3 1/4".
There isn't 100fps difference in their data from the .45/90 to the .45 3 1/4"

 

[Daryl S]

I really hope you find your load and keep us informed. I wanted to go that way and get a 500gr bullet to 2100fps, but I was afraid it was impossible to obtain if I stayed with COL of the standard 45-90, and under 50,000psi which some say is the limit for the modern steel 1886.

I started building a long throated 45-100 double instead.

You might find this info helpful.

45-90 Tale of 2 rifles

Is this fellow trying to say reamer when he says ring?

"The chamber ring that I purchased was for a 45-90 Winchester chamber I was pleasantly surprised to see that this ring gave me .200 free bore."

 

[mgstucson]

Is this fellow trying to say reamer when he says ring?

"The chamber ring that I purchased was for a 45-90 Winchester chamber I was pleasantly surprised to see that this ring gave me .200 free bore."

Yes

 

[Daryl S]

Just watched a video on the .45/90, .45/70 and .458 Marlin by Tim, the owner of Buffalo Bullets.
He says the .45/90, in the same rifle at the same pressures(I assume) will give roughly 15% higher vel. with the same bullet. Now, if it is possible to get the .45/70 to 1,650fps in a m86 with a 500gr. bullet, the same gun in .45/90, should get 1,897fps - close enough to call it 1,900fps.
I would believe the 2,100fps with a 500gr., maybe even a bit more, IF in a Mauser rifle, not a lever gun.
The Argentine Mauser just might do it.
I loaded the same ammo I used in my .459 2" in an Argentine Mauser in .45/70 and it gave duplicate vel. with the same bullets. I used the same load for all bullet weights: 350 @ 2,296fps, 400gr. @ 2,150fps and 500gr. at 2,059fps. This shows the 400 and 350's were not at the same pressure as the 500's, obviously. I got duplicate vel. using both H335 and IMR4320.
I tested John Buhmiller's primer on top of the powder, cup-down-theory for straight sided cases, briefly.
I was able to reduce the load by 8 gr. and got the same vel. Interesting experimentation. A move interrupted this 'work' & I never got around to it again.
My .458 2" had a 3/8" freebore/leade - BUT, it required a HEAVY crimp on the bullet to give good St.Dev's.
A Lee Factory Crimp Die would allow crimping any cup and core bullet, anywhere, so case capacity could be increased, just as I did with my .22 Hornet and .218Bee.
Buffalo Bore .45/90 ammo specifically for (I would suspect) a modern Model 86 Winchester runs a 430gr. hard cast flat nose at 2,150fps, for 4,413fpe.