Looking for .45-70 Trapdoor Data

[462]

Don't recall that I've ever asked for load data, but the time has come.

Rifle: Pedersoli/Navy Arms "Buffalo Rifle" rolling block. (Pedersoli states the rifle is proofed for loads to 29,000 psi, but not wanting to push it I've only used Trapdoor cast bullet data.)

Bullet: Midway factory-second 350-grain jacketed with an exposed lead round-flat nose. I've found plenty of 300-grain data, using H4895, Unique and 2400, but none for a 350-grain bullet.

Powders: Because of the last sentence, I'd like to use H4895 (have IMR 4895 but that's set aside for .223), Unique or 2400.

Looking for Trapdoor data only.

Thank you.

Michael

 

[oscarflytyer]

Look at, I think, Lyman 336/340 grn data. If you don't have any/can't find - pm me and I will dig some out and send.

 

[462]

I've looked in Lyman's 38th, 40th, 44th, 45th 49th and 50th, Hornady's 3rd, 4th and 9th, Hodgdon's web-site (Hodgdon, IMR, Ram Shot, Winchester and Accurate), Speer's 11th and 14th, Sierra's 5th and 6th, but didn't see anything closer than 300 or 325-grainers. Suppose, though, I could start somewhere in the middle of their data, just prefer to have 350-grain data.

 

[StrawHat]

Use the original gunpowder and stop worrying about it.

Kevin

 

[glassparman]

I only use black powder in mine. Load to just slight compression.

I can't help you on any smokeless data.

 

[RBHarter]

I would think that one could split the difference between the 32? and 405 3 ways loading from bottom of the lowest 1/3 to it's top and be ok barring some oddity like an unusually hard bullet or really long bearing length.

 

[fiver]

i bet 9.5-10grs of unique is below your 13000 CUP max window... by 1-2 cups.

i'd say 20grs of 2400 is borderline but close-nuff i'd do it if the gun is in good shape.

 

[Rushcreek]

Just use data for 405 gr bullets.
The 350s will go about the same speed but with less pressure.
Work up from there if you want.

 

[Rick H]

Speer Data seems to be the only one I see that uses H4895 for trapdoor loads.
Checked Lyman and Hornady, Nada for jacketed 350 gr. bullets and 4895. They do use it for Marlin 1895 and Winchester 1886 level loads. This is the Speer Trapdoor data:

 

[dale2242]

Just use data for 405 gr bullets.

This should work nicely.

 

[462]

With Unique and 2400, the powders I prefer to use, Lyman's 44th and 45th data for a 405-grain jacketed bullet are:
Unique: 11.0-grains to 15.0-grains
2400: 22.0-grains to 27.0-grains

With 385-grain cast bullets, 14.7-grains of Unique proved to be very accurate. With 405-grain cast bullets, 20.0-grains up to 24.0-grains of 2400, and 13.5-grains of Unique proved to be likewise.

Given I've more Unique, think I'll start with 11.0-grains.