.45-70 Loads for Trapdoor needed *UPDATE*

[K. Funk]

I am planning on loading 420gr hard cast lead loads for a Trapdoor rifle I recently bought. I am thinking along the lines of 35-40 gr IMR 3031. My typical load for the Marlin Guide Gun is 50gr with this bullet. I'm hoping to be able to use the reduced loads in both rifles, ie, a plinker load in the Guide Gun. Any thoughts?

Thanks,

krf

[BUFF]

My old Lyman #45 manual has a section for the Trap Door. The manual says, for a 405 grain jacketed bullet and IMR-3031, 34.0 grains (1137 fps) to 39.0 grains (1356 fps). 38.5 grains supposedly duplicates the factory load. This is with Remington cases and Remington 91/2 primers.

The closest cast bullet mentioned is 385 grains (it then skips to 482 grains). No IMR-3031 is mentioned, they recommend just Unique and H-2400. They don't mention IMR-3031 for any cast bullet for the Trap Door.

Unique, 10.0 grains for 1048 fps, to 15.0 grains for 1335 fps.

H-2400, 20.0 grains for 1191 fps, to 24.0 grains for 1385 fps.

The same manual uses -3031 for lever action Winchester 1886 rifles but emphatically warns against using the data for Springfields.

I'd use either black powder or a pistol powder.

[K. Funk]

Buff,

Thanks a bunch. With the pistol powder, do you need to buffer or something similar, say with kapoch, to keep the powder on the bottom of the case? I also have Clearshot I could try.

Thanks,

krf

[aardq]

First thing to remember is that the Trapdoor is the weakest action ever made. Your Marlin has a fairly strong action so any loads for the Trap will be just plinkers in the Marlin.

Having said that, my load for several thousand rounds of 45-70 was a 405gr cast lead bullet over 14 gr of Unique with a small tuft of dacron over the powder. That was about 25 years ago. Today I'd use grex or something similar to fill the case.

Have fun shooting the Trapdoor.

Dan

[BUFF]

The Lyman manual said nothing about fillers, but that's a pretty big case and a small powder charge. I probably would.

[MAINER]

Trapdoor Load

405gr Lead (sized .457)
36.0 gr----IMR 4198
Rem. primer
1417fps
Pressure <17000psi

Also IMR 4759---20.0grs. Adj.up or down a grain for accuracy. Powder bulks up well in 45-70 case, no need for fillers in these loads.

[K. Funk]

Had the Trapdoor out today. Wow, what a rifle!! I tried 2 loads. First was 35 grains IMR 4198 under 405gr cast lead. Didn't clock it, but it shot just fine. About 12" high at 100yds. Got about 4-5 inch groups out of it. Second load was same bullet with 2-30 gr Pyrodex pellets. Shot to almost the same POI. The smoke was a neat factor. I just gotta play with the sights to dial her in. Extraction and ejection was flawless.

krf

[pumpkinheaver]

Try some real blackpowder in it if you thought the pyrodex was fun!!!!!!!!!!!!