I was wondering if anyone loads 45-90 or 45-100 cartridges to higher pressures levels.
I see in my various reloading manuals that 3 pressure levels can be loaded in the 45-70. So I was interested to know if anyone loads these to old BP cartridges up to near 458 win mag or 458 Lott levels for use in modern strong falling block actions.

we are working on the 45-120, not the 90 or 100 at this time

results are pending
jeffe

My cartridge development book lists the 45-90 as having 5 gr less capacity than the 458, so the starting loads for the 458(35,000 psi+-)in my Hodgdon manual should work. I'm building a 45-100, which should have more capacity than the 458, so the starting 458 loads should be even milder.

jeffeosso - I have a .45-120 on a Ruger #1 and have loaded 96 grs. of WW785 and 90 grs. of IMR-3031 with a 500 gr. Hornady. I don't know what the pressures were but, even in a 13 lb. rifle, it was an eye opener. The rifle has a 29" half octagon/half round barrel about 1 1/8" at the muzzle. It is very accurate, shooting clover leafs with that load at 100 yards but, you can't keep the rifle on the forward rest without gripping the forearm. It usually winds up about 6" to the right of the bag after leaping about a foot in the air.

To anyone interested, I have a box (50) of 2.75" unfired, un-headstamped cases supposedly made by Winchester and a set of RCBS dies in .45-90 for sale. PM me if you're interested. Sorry about the commercial plug.