Looking to push a 405gr Lead 45-70 bullet about 1500fps w/ H4198

[Stormin.40]

I am going to load up a few rounds of 45-70 for a friends 1895 Guide Gun. This is a modern 45-70 lever action with an 18" barrel, he would like something around 1500fps. I am using Hodgdon H4198 and Laser-Cast 405gr Hard Cast Lead Flat Point bullets.

Hodgdon list max trapdoor loads out of a 24" barrel up to about 1450fps with 31gr of H4198, the Lever Action loads don't start until around 1850fps with 46gr of H4198 again out of a 24" barrel.

My gut tells me I should start at 31gr but I know these will be about 100fps slow and I would need to work up from there so I thought I would add a few grains and chrony to see where they end up.

Does 35grains of H4198 sound like a good place to start?
Any first hand experience with these components and gun?

 

[rcmodel]

Lyman #49 shows:
1886 Win & 1895 Marlin
IMR-4198
405 lead RNFP
24" barrel

36.5 Start = 1,533 @ 18,300 CUP
40.5 MAX = 1,717 @ 27,500 CUP

I'm thinking you will need to get pretty close to the max load to get an honest 1,500 with 6" less barrel.

BTW: The Hodgdon data you are looking at is for Speer jacketed bullets.

rc

 

[Stormin.40]

Thanks RC, I don't have the Lyman #49 manual, only their revolver/pistol manual and Speers manual, I have only been loading pistol up until now.

I am using the H4198 not IMR 4198 I know there is a little difference, I will have to pick up a Lyman manual now.

 

[ArchAngelCD]

I've been shooting a charge of 32.0gr H4198 with a 405gr lead bullet in my Trapdoor. I haven't sent any of those over the Chrono yet but I highly doubt that load will achieve 1500 fps.

I'm thinking you will need to charge ~39.0gr to get the velocity you're looking for but that's just a guess. A chrono will help a lot with that load...

 

[Stormin.40]

ArchAngelCD, are you shooting 32gr out of an original Trapdoor? I have some reservations using smokless in my original trapdoor even though it is in great shape and solid, the pressure curve is so much steeper for smokeless I wasn't sure it would be safe. I am working up to trying which is why I have the H4198 on hand.

 

[Kosh75287]

You might find it worth trying a slower powder, like IMR 3031, or something similar. You may find the velocity you desire more toward the middle of the range of data with these powders, since their pressure curves are generally a little more gradual.

 

[ArchAngelCD]

ArchAngelCD, are you shooting 32gr out of an original Trapdoor? I have some reservations using smokless in my original trapdoor even though it is in great shape and solid, the pressure curve is so much steeper for smokeless I wasn't sure it would be safe. I am working up to trying which is why I have the H4198 on hand.

Yes, I'm firing that ammo in an original 1884 Trapdoor. I only use load data specifically written for the Trapdoor so as not to stress the rifle. Hodgdon and others have plenty of data for building safe Trapdoor ammo. I shoot H4198 all the time with no ill effects at all. I just loaded up some ammo with IMR3031, Trail Boss and AA5744 to try out for accuracy. From what I read AA5744 is supposed to work very well in large Black Powder cases like those of the 45-70.

If you are still worried about using smokeless powder in a Trapdoor you can always use Pyrodex instead. That is a Black Powder that's been slightly altered to make it safer than original Black Powder. I have used it and it works just as well as Black Powder.