Plain Base 45 70 How Fast?

[Spokerider]

How fast can a 350gr to 405gr plain base boolit be driven in a 45 70 without leading problems?

Alloy of; 50% COWW + 2% tin added, with 50% Pb.

Rx7 powder.

Trying to decide between a GC boolit and a plain base hunting boolit.

Thanks.

[Doc Highwall]

I would say 1300-1400 fps. With a gas check bullet you could either shoot a softer alloy or a higher velocity.
It also depends what you are going to hunt and at what distance.

At black powder velocities a plain base bullet has killed millions of bison.

[Texantothecore]

I would say 1300-1400 fps. With a gas check bullet you could either shoot a softer alloy or a higher velocity.
It also depends what you are going to hunt and at what distance.

At black powder velocities a plain base bullet has killed millions of bison.

About 60 million bison.

[Bullshop]

You are really asking two questions and the answers are going to be different.
#1 How fast without leading.
answer - faster than you might expect. With a good lube and a good boolit fit with an alloy hardness appropriate to the pressure possibly near 2000 fps.

#2 How fast with accuracy
Under the same conditions as above possibly up to 1500 fps. Some folks have claimed even higher.
The point I am trying to make is that the two wont be at the same velocity. Accuracy will fail before leading begins if used under the conditions mentioned in #1.
Sooooooo, we shouldnt be asking or worrying about leading but instead about accuracy because the one will preceed the other.

[44man]

You are really asking two questions and the answers are going to be different.
#1 How fast without leading.
answer - faster than you might expect. With a good lube and a good boolit fit with an alloy hardness appropriate to the pressure possibly near 2000 fps.

#2 How fast with accuracy
Under the same conditions as above possibly up to 1500 fps. Some folks have claimed even higher.
The point I am trying to make is that the two wont be at the same velocity. Accuracy will fail before leading begins if used under the conditions mentioned in #1.
Sooooooo, we shouldnt be asking or worrying about leading but instead about accuracy because the one will preceed the other.
Wisdom I can't add too!

[DrCaveman]

I ran the 405 in front of 40 gr rx7 for 1527 fps in a handi rifle.

Load should be in the marlin/lever action level. Pressure is totally speculated but ill guess it's around 20000 cup

No leading, decent accuracy. Stout kick.

I liked varget better at the same velocity. Load there was 49.5 gr, kick was less and accuracy better.

Lube was nothing special. Bet both loads would do better with a good lube

[45 2.1]

Accuracy will fail before leading begins if used under the conditions mentioned in #1.

Actually, he made no mention of how the boolit was treated, just the alloy. Put buffer under it, a wad under it, heat treat it, freechec it, patch it....etc. and you will have accuracy long after your able to stand shooting it too many times.

[fredj338]

I can get 1500fps w/o serious leading from clip ww or water dropped range scrap.

http://img.photobucket.com/albums/v703/fredj338/DSC_0041.jpg

[Spokerider]

Thanks for the replies.

Yep, I figured accuracy would suffer as / or before leading began, however, this will be a close range hunting boolit for large coastal black bear, as in, at a distance of 5m to 75m., so I don't need one MOA accuracy anyway. I do want penetration, and I do want some expansion. What I do need is for the bear to die quickly, in the event it's actively chewing on one of my dogs. I also need for the boolit to hold together and not fragment. Ricocheting boolit fragments can wound / kill nearby dogs. I may also use the boolit on panther and blacktail deer.......but they are not difficult to kill with any .458 boolit.


As far as lube goes, I don't recall exactly what I have. I bought a few of sticks of different types from a seller on here some time ago.

The gun? A 4.5lb contender......which means keeping the load to trapdoor pressures.

[Spokerider]

fred,
Nice expansion with that boolit.
What did it hit?

[Larry Gibson]

If the rifle can handle the psi you can drive them to 2300 - 2400 fps without leading if the right alloy/lube is used. However, most often accuracy will go south around 1500 - 1600 fps.

Larry Gibson

[btroj]

I have gone unto about 1650. That load leads a bit, not enough to destroy accuracy until 20 shots or so. Killed a couple Bears with it.

I have decided that much velocity isn't needed. I now prefer 1350 to 1400 for my rifle. Much easier on me too.

[mpmarty]

Faster than you want to hang on to a contender shooting it. In a rifle I get near 2000 fps easily with 350gr plain base boolits and can't stand the recoil at that level anyway. I know I'm a wuss.

[Spokerider]

If the rifle can handle the psi you can drive them to 2300 - 2400 fps without leading if the right alloy/lube is used. However, most often accuracy will go south arough 1500 - 1600 fps.

Larry Gibson

With the alloy mentioned, do you feel that 1500-1600 fps is an attainable velocity, or do will I need to make some alloy changes for a plain base boolit?

[btroj]

I think it is very possible with that alloy. Good fit Will make it far easier. I also prefer a slower burning powder for pushing them that fast.
I used H322 for my loads. H3895 wpuld work even easier in my opinion. A gradual push is better than a hard kick in the pants.

[Larry Gibson]

With the alloy mentioned, do you feel that 1500-1600 fps is an attainable velocity, or do will I need to make some alloy changes for a plain base boolit?

It's certainly possible to approach 1600 fps with a PB'd cast bullet, even one that soft. However, as mentioned all must be right as to fit and like also mentioned I too prefer a slower burning powder than RL7 for the task. Worth a try though. I suggest a dacron filler of 1 - 1.5 gr with the RL7. I also suggest a good soft lube such as a NRA 50/50 lube.

Larry Gibson

[DrCaveman]

Trapdoor pressure levels will limit your velocity to a large degree. But according to Lyman cast bullet handbook #4, 39 gr will get you almost 1600 fps with a 24" barrel. Pressure is stated as 17,900 cup.

This load could prob use a filler as Larry suggests.

I think it will kick a bit more than a slower powder like the ones mentioned above or hodgdon Varget. Seems that such a light gun would be easier to shoot with the softest recoiling loads for a given velocity.

[44man]

I shoot PB in my 45-70 revolver all the time at 1600 fps with no leading. I use a harder boolit but have shot softer and they did not lead but I had a lot of fliers.

[Spokerider]

Thanks for the help.
I'll prolly get a plain base mold then.
I have some H322 to try also.

As stated, the trapdoor pressures will prolly be a velocity-limiting factor, as will the 14" barrel.