45-70 load in a Trapdoor

[double8]

I've been shooting 45-70 handloads of 10 gr Unique pushing a 405 gr boolit at about 1000 fps in my 1886 Extra Lightweight. My friend would like to shoot a few out of his Trapdoor. He's been shooting 70 gr FFg with that same boolit.
I would think that 10 gr Unique load should be safe in the Trapdoor.
Your thoughts please..

[johnson1942]

blackhorn 209 powder, it fills the case like black powder and is only 15 percent stronger. very clean and very accrate. you dont need any fills and again just as accurate as real black. just cut back 15 percent by volume of what you would use for real black. still be able to put the bullet on the powder. many many out their are useing it in a 45/70.

[Tatume]

You might want to move this to the SingleShot forum; lots of good, informed folks there.

In the meantime, there's lots of good Trapdoor loads in all the reloading manuals. I recommend sticking with known, safe loads in the old guns.

[StrawHat]

I have two trapdoors. They seem to thrive on blackpowder, 2F and 3F. Anytime I venture into the world of smokeless, groups tend to open, sometimes double. For me, the original gunpowder is the way to go.

[mooman76]

There is load data in Lyman and I believe Lee manuals specific to the Trapdoor for light loads in the 45-70. Of coarse your Trapdoor needs to be in good enough shape to handle smokeless powders and if you are not sure, you should have your gun checked out by a gunsmith. I went up to 12.5 gr of Unique in mine but was showing pressure signs when I used a filler with this load so I backed off some.

[mazo kid]

These are black powder guns and that is all I ever use in mine. Unless your boolit fits the bore tightly, I don't think you will get great accuracy out of a Trapdoor. The BP bumps the boolit up to fill the grooves better.