Lead bullet pressures are greater than jacket bullet pressures of the same weight

Here is an interesting tidbit...I would have assumed the opposite.

Here is a quote off the Western Powders blog from their ballistics labs:


http://blog.westernpowders.com/2014/...allistics-lab/

Lead Bullet Pressure

Actually it is a general question: All things being equal do lead bullets generate more pressure than jacketed bullets?

Yes, they do. It all comes down to the frictional co-efficient. Gilding metals like copper slide more readily than lead does on a steel surface. You can write your name on a piece of paper using a lead bullet much more readily than you can with a copper one. This tendency to smear, which is why it leaves a track on paper is also why it tends to grab the barrel more quickly and increase pressures. Using jacketed bullet data with a lead bullet of the same weight will result in higher pressures, everything else being equal.

It may sound like common knowledge, UN arguable. I don't think like that and your not taking BOOLIT lube in to consideration in the equation. I'm going against the experts on this one and could be dead wrong.

{shaking head in disgust}

Gear

I know one thing most of my boolits don't leave any lead smeared inside the barrel EVER, some for years...The other thing, most of my guns have to be cleaned after using jacketed bullets eventually. (if I used a jacketed bullet)

I may well be wrong and it wouldn't be the first time. If leaving a lead smear on paper shows it has a higher coefficient of friction, then the graphite in a pencil must really be high! Also try pushing a jacketed bullet through a barrel and compare that to a lead one.

Quote:

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Originally Posted by 10mmShooter

Here is an interesting tidbit...I would have assumed the opposite.
Here is a quote off the Western Powders blog from their ballistics labs:
http://blog.westernpowders.com/2014/...allistics-lab/
Using jacketed bullet data with a lead bullet of the same weight will result in higher pressures, everything else being equal.

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Quickload will show you what the real differences are. Western Powders has it backwards.

[smilie=b::not listening:

With all the ability to measure pressure these days. ........

Larry Gibson

In my experience all else being equal a cast lubricated boolit will give lower velocity of in the neighborhood of 150 fps depending on the type of load and cartridge.
Since I can not accurately measure pressure but can accurately measure velocity I use velocity as an indicator of pressure.
In my own observations lower velocity reads as lower pressure.
Another point I would like to make is this if a jacketed bullet has less friction resistance in its passage through a barrel why then do we not use jacketed bullets to slug our barrels?

Since a cast lead lubed boolit of the same weight of a jacketed boolit with the same powder charge generally reaches a higher muzzle velocity (often 150 to 250 fps.)… At least that is what I have found on my home range and chronograph. Depends on the lube I guess.

I can't believe that Western Powders thinks there's lead in a pencil? :veryconfu

It says it's a blog, did Western Powders make that statement or someone with their head screwed on backwards.

Attachment 102410

Old wives tales will never die.

Rick

That's just silly.

BULLhocky.

Why do you think that all plain journal bearings like in every car out there are lined with LEAD alloy?
Because it has extremely low coefficient of friction on smooth steel when properly lubricated. Lower
than anything else or they would be using the "anything else".

Bill

This belongs in the "silliest things you've heard" thread a few lines down. :)

I think they got it bassakwards;)

Maybe someone should tell them.

Quote:

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Originally Posted by 10mmShooter

Here is an interesting tidbit...I would have assumed the opposite.

Here is a quote off the Western Powders blog from their ballistics labs:


http://blog.westernpowders.com/2014/...allistics-lab/

Lead Bullet Pressure

Actually it is a general question: All things being equal do lead bullets generate more pressure than jacketed bullets?

Yes, they do. It all comes down to the frictional co-efficient. Gilding metals like copper slide more readily than lead does on a steel surface. You can write your name on a piece of paper using a lead bullet much more readily than you can with a copper one. This tendency to smear, which is why it leaves a track on paper is also why it tends to grab the barrel more quickly and increase pressures. Using jacketed bullet data with a lead bullet of the same weight will result in higher pressures, everything else being equal.

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I have always felt this way about lead bullets. The size, better pressure seal, & higher friction raise pressures. Not a lot, but a bit higher than equiv jacketed loads. I don't believe lead in fuels is the same as pushing a lead bullet down a bbl. Until I can get a Pressure Trace setup to prove or disprove it, that is my story.

Sometime I just have to SMFH

There's a gentleman who posted above who has pressure test equipment and has done a good deal of pressure testing with cast and jacketed. He's not speculating when he signals his disagreement with the premise.

That is another case of an "expert" mouthing off about lead bullets.


Lyman 49.

.30-30

170 grain jacketed
3031 28.5 gr 36,900 CUP


170 gr Cast
3031 28.5 gr 32,500 CUP


Examples are not easy to find but if you look there are plenty of them in there.

I have never seen a case where the cast bullet produced higher pressure than jacketed.

Quote:

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Originally Posted by LynC2

I may well be wrong and it wouldn't be the first time. If leaving a lead smear on paper shows it has a higher coefficient of friction, then the graphite in a pencil must really be high! Also try pushing a jacketed bullet through a barrel and compare that to a lead one.

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Touche'