45-70 "short"

[TheBear]

ive been experimenting with super light 45-70 loads for some time now, no matter what i do, i always end up with bad accuracy because of very inconsistent velocitys. the reason for the ups and downs in velocity is the tiny powder charge in the huge 45-70 case. Sometimes all the powder is near the primer - little or no unburned powder - high v0, sometimes more of the powder is right behind the bullet, far away from the primer - lots of unburned powder - lower v0. I can point the gun upwards before every shot, making the powder fall back to the primer then i get good accuracy (tried it) but thats just ridiculous and not a real solution for my problem...

so thats my plan:
take some regular 45-70 brass, trim them down to a 1/3 of their length and use magnum primers.

45-70 headspaces at the rim so i shouldnt have problems chambering and shooting those 45-70 "short" cases.

What do you guys think??

[mavracer]

45/70 is a tapered case. If you trim it to about 1.4" you can seat a .475 bullet in it. http://en.wikipedia.org/wiki/.475_Linebaugh

[NoSecondBest]

mavracer has already pointed out the first pitfall of what you're doing. I don't even understand what you're trying to accomplish. If you want to shoot something that light recoiling, and at a very low velocity, you'd be way ahead of the game to just get a shorter case cartridge to begin with. Rebarrel your gun or get a different caliber. There just doesn't seem to be any logic in what you're trying to do. FYI, there are a lot of "light" loads available for the 45-70 that don't require ruining the cases and jumping through all the hoops you're jumping through. Do a search on 45-70 and round balls or 45-70 light loads. Lots of info will pop up. People are shooting light loads out of these things all the time, mostly with cast bullets and round balls and aren't having all the troubles you're having.

[Clark]

I have been working on reduced 45/70 loads for a long time.

I have got it down to sounding like a pellet gun and killing a raccoon with a body shot.

I started out reducing the powder charge.
1) Put 1 gr of Bullseye in the case. Put the cast bullet in the case mouth.
The load is quiet, but the bullet bounces off cardboard.

2) Put 1 gr of Bullseye in the case. Shove wads into the case. Shove the cast bullet down into the case to compress the powder.
The load is quiet. The bullet goes through 1" of wood.
But the accuracy is terrible. The jump to the lands is in inches.

3) Fill the case with steel. Drill a flash hole. Put 1 gr of Bullseye on top of the metal. Put a bullet over that. That load can be silent but deadly, but it may be noisy and the bullet may fall off the case. The bullet must seal the case at the lands. The metal must be tall enough to push the bullet into the lands. There must be a crimp or glue to hold the bullet in place. The metal can shoot out. The metal can take a long time to machine. The metal may not fit.

4) Make a spread sheet for the difference between the taper of the chamber and the thickness of the cross section of the brass at any point in 0.1" increments from the case web. Make the filler from Aluminum 1/2" round stock. Make a list for the DRO of the lathe. Clean the new case, clean the insert, and shove it in with Loctite and force. Drill the flash hole big enough for what will be used to de prime the case.

Shown in the pic are:
1) a 45/70 case with the metal inserted and drilled, with a drill going through the large flash hole.
2) The aluminum insert.
3) A round loaded with a 145 gr .458" cast bullet
http://westernbullet.com/45riflecaliber.html

Here is some of my test data from 5/11/2010 with a 22" barrel.
[The longer the barrel the greater the volume for the gas to expand to non super sonic escapement pressure .. one atmosphere above ambient. So the more barrel length, the more velocity is possible and still be quiet.]

0.6 gr Bullseye .....287 fps........ quiet
0.7 gr Bullseye .....384 fps........ quiet
0.8 gr Bullseye .....354 fps........ quiet
0.9 gr Bullseye .....388 fps........ hollow sound but quiet enough
1.0 gr Bullseye .....441 fps........ sounds like a loud pellet gun, but no blam
1.1 gr Bullseye .....418 fps........ sounds like a loud pellet gun, but no blam
1.2 gr Bullseye .....536 fps........ sounds like a very loud pellet gun, but no blam

[flashhole]

Buy a pellet gun.

[Clark]

Pellet guns will kill a crow or a squirrel with a neck shot or a head shot.

But it takes a big hole to stop a raccoon with a body shot.

[Valornor]

What about using a bulkier powder like Trail Boss? It's a pistol powder....its slower then Bullseye, and faster then Unique. It should yield you more consistent velocities. I don't any experience working with this powder but from what I have heard it's probably going to be more suitable for your application then bullseye.

When loading for cast I did it for both 7.62x54r and 303 Brit. I was loading a 154grn cast slug over 11.5grns of unique to give a velocity around 1500fps. Obviously the case volumes are far different and rounds are worlds apart, but in my eyes the concept is the same. The recoil was a like a .22. I great plinking load that would have more then dispatched rodents.

In short I would try a bulkier/slower burning pistol powder.

[Salmoneye]

300gr cast at less than 1000 fps slow enough for you OP?

http://www.gmdr.com/lever/lowveldata.htm

[TheBear]

salmoneye:

its not about velocity, its about power. a 300 gr bullet at 800-900fps is still pretty powerfull.
a 150 gr round ball at 650fps is more like what id like to use.

Clark:

thanks for the great info. you sure have some experience with reduced power loads.
Why did you never try to trim down the cases to eliminate the unnecessary space? should be much easier then building aluminium/steel inserts.

[Clark]

I have built a 50 cal rifle [cut down 56-50 case] with a 60" barrel that pushes 186 gr at 800 fps and sounds like a pellet gun.

I have to load it with two presses to form a Lead ball into the case and to make the bullet seal the gas at the lands.

[m&p45acp10+1]

If worried about case fill use Trail Boss. It works great for reduced loads, and still has plenty of case fill. I have also had good results with Red Dot. I use 12.5 grains with a 405 grain hollow base that gave around 1000 FPS roughly. 13 grains with 350 grain beveled base gave similar velocity and was low recoil.

[Jim Watson]

I think the long jump through the chamber would greatly reduce the accuracy of a .45-70 "short."

There are powders meant for the job, 4759 and 5744 that I know of.
I have read that 2400 is less position sensitive than most, but you must be careful loading a large volume cartridge with it.
Everybody is nuts over Trail Boss, which is very bulky and will work if you only need about 1000 fps.

There has been some work done with reduced volume cases. You don't have to take it as far as Clark. Somebody picked a rimless case with a head diameter the same as the I.D. of .45-70 and crammed a cut-off case down in the .45-70s. Seems like a long primer flash channel.

Rocky Mountain Cartridge will lathe turn cases of about any desired internal volume.

A straight case like .45-70 is the best chance to work safely with fillers over a light load.

[schmellba99]

Way back in the old days they used to use fillers to put between the powder charge and the projectile.

Surprisingly, Spanish moss made a great filler. It does not harm the barrel, and what doesn't burn actually helps clean fouling out of the barrel. It was also used extensively in muzzle loading as a wad when the explorers did not have normal silk or cotton to spare.

I would think that putting your charge in, then using a compression disk to keep the powder in place above the primer, then using a filler to take up the void between the projectile and the compression disk would be the best, and safest, method to get your low velocity and still maintain a short jump to the lands from the case mouth.

[jkpq45]

OP, what powder were you using for your loads?

As suggested by other posters in this thread, small charges of faster powder work well.

I load my 45-70 with Winchester LP/LPM primer, 10gn of Win AA Plus (like Hodgdon Clays) under a 405gn Lead pill seated in the crimp groove. No fillers.

Definitely subsonic, light recoil, good accuracy.

[PawPaw]

Way back in the old days they used to use fillers to put between the powder charge and the projectile. Surprisingly, Spanish moss made a great filler.

I still use fillers in reduced loads in the .45-70, but nowadays instead of spanish moss, I use pillow dacron. It works great. I've never experimented with severely reduced velocities in that caliber, but I don't see why it wouldn't worki.