View Full Version : .45-70 Loads for Trapdoor needed *UPDATE*
December 03, 2006, 07:55
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?
December 03, 2006, 19:24
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.
December 03, 2006, 19:52
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.
December 04, 2006, 00:31
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.
December 04, 2006, 01:03
The Lyman manual said nothing about fillers, but that's a pretty big case and a small powder charge. I probably would.
December 04, 2006, 10:47
405gr Lead (sized .457)
36.0 gr----IMR 4198
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.
December 29, 2006, 12:17
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.
December 31, 2006, 16:09
Try some real blackpowder in it if you thought the pyrodex was fun!!!!!!!!!!!!
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