I'm having miss fires in my 45-70 with a 305 grn bullet in front of 40 Grains of IMR3031,
The primer will actually push a column of the powder and bullet in the rifling.
Factory load work okay.
I've reloaded for 40 years and have never seen this happen before.

Any ideas?

HAve seen this...pushes a "plug" of powder...powder kind of semi-melted into a mass that needs to be removed with a rod. Grains look kind of opaque, as if the coating got burned off but the fire never really got going.

Stop shooting those loads....whatever is goin on PROBABLY isn't dangerous, but get the feeling that it COULD be.


Best guess is that the volume increases much faster than the powder's ability to generate pressure...but am not at all sure what the effects might be if htat powder charge decided to burn once it's jammed a distance into the barrel.

I'm having miss fires in my 45-70 with a 305 grn bullet in front of 40 Grains of IMR3031,
The primer will actually push a column of the powder and bullet in the rifling.
Factory load work okay.
I've reloaded for 40 years and have never seen this happen before.

Any ideas?

I had similar results when I tried downloading my 454 Casull. I had this problem with a specific powder with low load densities with lead bullets. I started using a "buffer" and I had no more problems. When dealing with a large case like the 45-70 you need to build pressure slow so the powder has a chance to burn. IMR 3031 is a fast burning powder used a good bit in .223, although I do know that there are several guys here on the board that use it for 45-70. I suggest using a Dacron wad or some type of buffer material like PSB if you insist on IMR 3031, and I would think that your burn rate problems would go away.

It could be the load, as that's about 30% lighter than the starting load of 51 grs. in my manual. If this were a faster powder, the reduced load would not cause this.
You could use a duplex load, if you really wanted to use the 3031, by putting a priming charge of one grain of Unique under the 40 grs. of IMR 3031. This would ensure complete ignition, which is what you're not getting with this light charge of slow powder.
IMR3031 is "fast" for a rifle powder, but not fast as compared to all powders. There are probably 35-40 powders faster than IMR3031.

I'm having miss fires in my 45-70 with a 305 grn bullet in front of 40 Grains of IMR3031,
The primer will actually push a column of the powder and bullet in the rifling.
Factory load work okay.
I've reloaded for 40 years and have never seen this happen before.

Any ideas?
same thing happened to me a couple days ago, or should i say a bud who was with me. i knew better, i always tilt , shake the powder back against the primer. then fire always noticing the slow ignition with a light charge , i shoot a high wall 45/70 . i never liked the idea of wad or fillers, but fact remains, ya still got to keep the powder with a little compression to be sure. i found some stuff called puff-lon to fill the light charged cases that should work well. do a search by name or go to buffalo arms. hope i could help, john

We are used to seeing unburned 3031 in .45-70 loads. I seem to recall starting at 44 gr. with a 405 gr. jacketed many many years ago. Don't count on the charge, I've got CRS bad! I don't remember any ignition troubles but that was also a heavier bullet. If you are looking to create a mild reduced load you might consider Unique or Red Dot. Personally, I like Red Dot as it doesn't appear as position sensitive as Unique. I shoot 9 gr. Red Dot and a Lee 450 gr. cast bullet of air cooled wheel weights in a Rolling Block sporter. Muzzle blast and recoil is mild and it is extremely accurate in this rifle.

Another nice light load is 28gr Alliant 2400 and the 350gr Hornady RN.

40 grains of 3031 powder will always leave unburned powder grains in the barrel of any of my 45/70 rifles.
I sugest that you abandon 3031 for 'lighter 'loads,and try Reloader 7.that is just a little quicker.You may,or may not need a filler with that powder.498 is quicker yet and usually needs a filler.Dacron or PuffLon will be fine.
Frank

If you want to use up your 3031 before you switch to a better choice, you can put a duplex load together using a fast burning powder such as Bullseye or Unique. One or two grains dropped into the case before loading the charge of 3031, 40 grains will ignite it and burn cleanly.

Wow!
I am somewhat surprised at what I am reading. I stay away from fillers personally. And the idea of duplex powdered loads, give me the heebee geebies. Not to discount those who want to, but I would not use them myself.

As far as the IMR3031, I have used this powder in 45-70 for I guess 20 years? My everyday load is 36 grains with a 405 grain cast. Never had a problem and I've shot a lot of them.

One thing worth mentioning though, is the unburned powder. After every loading, I tumble my brass before the next loading. I some of that unburned powder staying in the cases? Then I always check the cases and primer pockets for tumbling media before loading. Then I look them over again.

Also make sure that you have a good crimp on your finished rounds. 30 years ago, I had an old reloader, tell me that IMR powders need a good crimp. That's just what I do...
Regards
Bestboss

I would think that the reduced load of 3031 and the lighter bullet creates a very low pressure load, and it would appear that it is well below the optimum operating pressure for 3031.
I note that some have used that powder with a heavier bullet, which would appear to create enough pressure to allow the 3031 to be better consumed.
I tried the classic 3031 loads in my .45-70 and I was never satsified with the amount of unburned powder that was present in the barrel, and sometimes falling back into the action. The amount of pressure required for proper use of 3031, in my opinion, created too much velocity (and recoil) for me to use.
I have gone to faster powders such as IMR 4198, Reloder 7 and 2400 for slightly slower loads.
I would save the 3031 for some other cartridge or load.

Have also seen this with a 45-70, but my load was using 2400. Would push the bullet into the bore about 2" and jam a wad of semi-melted scorched powder behind it. Have to kind of chip the powder mass out as it's congealed into an almost solid wad.

Powder is kind of translucent looking...melted is a good term...like it got started burning, then the fire went out.

That's about what I'm guessing happened...the increase in volume out-paced the rise in pressure. Only happend with light(short) bullets in a barrel with a long lead to rifling...a "free bore". Best guess is that the near zero resistance of that "freebore" let the bullet move ahead fast, and that sudden increase in volume litterally let the powder's burn never reallly get going.

Same charge...bullet seated so tha case had the same volume (bases set to the same place) BUT with a longer/heavier bullet so (1) there is more inertia resistance and (2) the bullet is right up against the lands for engravement resistance. Worked fine with the same powder charge....but changed loads just to be on the safe(er) side.
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A wiseer shooter than myself warned me that I was very close to runing that barrel. He pointed out that something evil could eaisly happen if that powder charge decided to start buring again once the bullet was stopped 2" down the bore. Sounds like a real good way to ring a barrel. If the shooter noticed anything at all, it would have been the delay we get from an hang-fire.