Help with load - Off Topic

[dead-bird]

The Lyman No. 49 reloading manual lists .45-70 cast bullet loads for the Trapdoor, 1886 Winchester, 1895 Marlin, Ruger No1 & No3, and T/C Contender.

For what it's worth.

IMR4198 is listed for every gun in almost all bullet weights.

No H4198 is listed at all.

[dellet]

Hodgdon load data lists both IMR and H4198 for loads in all types of rifles and also pistols using the 45-70. Cast bullets are limited to 45-70 trapdoor and pistol. Col for 300 grain cast is 2.465 vs 2.525 for 300 grain jacketed. For comparison I think it is safe to ignore the action type as long as barrel length is reasonably close. For safety disclaimer Hodgdon lists 35.5 as max charge for 300 grain cast and 55 grains for jacketed. This gives velocities of 1418 and 2076 respectfully.

According to Hodgdon 30 grains of H4198 behind a 300 grain cast bullet produces 1390 fps at 14400cup. assuming the trapdoor has a 18-20 inch barrel, I would assume this load would also push a 300 grain bullet out of a lever gun.

Hodgdon also lists a starting load for a 300 jacketed bullet using H4198 that is safe. This load is 45 grains, 1800 fps and 16700 cup. Seems like a huge increase in powder of little gain in velocity. The big difference in these loads is the COL. The jacketed load length is 2.525.

The failed loads in question used according to hodgdon data for pistol and trapdoor were probably loaded too long for the bullet as they were loaded to 2.5+.

From my experience with 45-70 I really think that with 42 grains of H4198 the bullet should have exited the barrel. The first three did. I would question:

1. Primer seating, Because of light strike marks and delayed ignition. (my understanding of cci BR vs regular primers is quality control. If they have a harder cup also, the Marlin may not have enough hammer to properly ignite)

2. Cast bullet, actual size and lead content. Some cast bullets for the 45-70 can be purchased basically as a soft cast suitable for black powder cartridges. If there was significant lead fouling going on in the barrel this might explain a gradual increase in barrel restriction to a point of sticking a bullet.

From the description of the problem, I think that it is more than just incorrect COL. as you seem to have mixed and matched jacketed loads with lead bullets. I am sure there is a reason Hodgdon lists the max load of H4198 with a cast bullet at 1600 fps and 16100 cup and IMR 3031 at 2000 fps and 23800 cup for the same cast bullet.

My guess is the H4198 burn rate is too much for the cast bullet, since the action can handle the higher pressure. Using a 300 grain Jacketed bullet Hodgdon lists 55 grains of H4198 at 2221 fps 27600 cup with a COL of 2.525 would suggest the problem is the combination of burn rate/temp and cast bullet being the problem.

Again probably more than one problem starting with using load data for a jacketed bullet, to fire a cast bullet. It would seem you are having a problem igniting an overcharged load.

Hope that helps. I enjoy the 45-70 but there are many variables and combinations in load data. Imagine the confusion of a new loader hearing you can use 70 grains of any cartridge powder in a 45-70 and that it is impossible to over load the cartridge. Absolutely true as long as it is BLACK powder, and you understand cartridge is the grind size.

one last thought, I do shoot both black and smokeless in the 45-70. If you think keeping .223 mags separate from 300 mags is difficult. All my cast rounds are black powder, all my jacketed are smokeless and they are in clearly marked containers.