Morning at the range with .54 GPR

[paulvallandigham]

Take another look at the manual. This may be the Maximum load they authorize you to shoot. This is intended for use with Conicals, Not PRB. Its somewhere short of a " Proof " load( which we don't really do in the USA) and what the company and its attorney's feel they can safely defend if the barrel fails and you take them to court in a products liability suit.

The Davenport formula is for shooting PRB out of all barrels. Its based on the ability of a given amount of powder to burn in a given length of barrel. The formula is 11.5 grain per Cubic Inch of bore. It works with both FFg and FFFg powder. Since I have never shot Fg powder other than in a cannon barrel, I can't say anything about the formula for cannon use, but I suspect it holds.

Davenport was the master armoror for the U.S. Navy in both WWI and WWII. He knew his black powder, because all the battleships used black powder to fire projectiles miles away and hit targets as small as a pickup truck. The last Battleship, the Missouri, still had such guns when it served in Desert Storm in 1992.

You can stuff more powder in the barrel. No doubt about it. I have done so. In most barrels you do little harm other than to your shoulder. Half the weight of the extra powder becomes recoil.

There is a diminishing return on powder used, versus velocity gained after you exceed the max. efficient load. That means, in layman's English, that you are getting less bang for your buck!

I suggested that you do penetration testing, in order to help you satisfy yourself that those loads you are using are Way TOO MUCH powder. That is how I taught myself that lesson. Listening to someone else with more experience should be enough, but on the question of power, we guys seem to have a drain hole in our heads, and only seeing it ourselves makes us plug the leak and believe what we are being told. Been there; done that! :shocked2: :rotf: :surrender: :cursing:

The purpose of this forum is to share information with each other, so that we can all spend more time enjoying shooting, and less time making our own mistakes. You are free to go your own way.

Best wishes. :thumbsup:

 

[HardBall]

Have any of you every done penetration testing with your loads? And compared them to shooting lesser loads?

I did so using a 60 grain charge in a .50 caliber rifle, and then a 100 grain load in the same gun, same Patch and ball, and saw absolutely NO deeper penetration using the heavier charge, out of a 39 inch barrel.

This is true since a pure lead ball deforms, or flattens, easily. The faster moving ball, of pure lead, will flatten out and increase in diameter upon impact which in turn will decrease it's penetration due to the increased resistance. The slower moving ball will flatten out less upon impact, not increasing its diameter as much therefore penetrate about as well as the faster moving ball. However, the faster moving ball will create a larger, though not necessarily longer, wound channel. In this way the round ball is remarkable self adjusting. This, I believe, is why the round ball works so well as a hunting projectile even though it looses velocity so rapidly on it's way to a target.

If we were shooting hard steel balls which did not deform (mushroom) but maintained their original diameter, the faster ball would allways penetrate deeper than the slower ball- all other things being equal.

If you do penetration testing, I think you will be impressed at how much penetration you get. You also will find that penetration is related more to the weight of the ball than the Muzzle velocity.

I disagree, Paul. Momentum, that is, mass x velocity, is an indicator of penetration and this formula puts the weight of the ball and its velocity on equal footing. What this formula can not take into account, however, is the deformation, with it's increase on diameter, of the round lead ball- which I just discussed.

 

[paulvallandigham]

Both the balls fired in my test were recovered and were equally deformed. I give you the point that I did not measure their RATE of EXPANSION as they went through 6 pine 1" boards spaced 1" apart. We did look down between each of the boards and noticed no real difference in the amount fo splintering on the back sides of the boards for the two different loads. Box was about 20 feet from the muzzle, so I was basically testing MV, and not some practical down range velocity, too.

You should consider that about 25% of the velocity of any RB is lost in the first 50 yards, and that 45% of the MV is lost in the first 100 yards. So, in real world terms, driving the ball faster only results in it slowing down faster, so that at 100 yards, the difference in velocity is not very much. I suspect that is why performance is so similar at those kind of ranges shooting RB, regardless of what load is used.

Data printed in this forum by another member for a .50 cal. RB fired at 1900 fps!!! Showed velocity at 50 yards to be only 1409 fps. and at 100 yards, only 1041 fps. That is a 25.9% loss in velocity at 50 yards, and a 46.2% loss at 100 yards. Using a couple of sources of loading data, I believe 100 grains of FFg can generate 1900 fps. in some .50 cal. rifles, shooting the PRB.

By comparison, it takes 120 grains of FFg powder to drive a 530 Diameter RB at 1900 fps. Mark's 75 grain load should produce about 1485 fps. in a .54, more than enough energy to kill any thin skinned game animal in N. America, without tasking the barrel or stock of the rifle, or the shooter's shoulder. And a .54 RB has plenty of " Whompability", based on all the statements of members here on that score.

 

[Kentuckywindage]

I saw on myth busters where they were doing penetration tests and the slower moving projectile had more penetration where as the fast moving bullet fragmented and came apart.

They were shooting a big modern .50cal, a blackpowder .50 and a 9mm. The 9mm and BP .50 won the penetration test.

 

[Swampman]

I may try some of those OP wads. Are yours the pre-lubed kind? What brand are you using?

 

[paulvallandigham]

I have the Walter's Vegetable fiber wads, Mark.

 

[HardBall]

Mark's 75 grain load should produce about 1485 fps. in a .54, more than enough energy to kill any thin skinned game animal in N. America, without tasking the barrel or stock of the rifle, or the shooter's shoulder. And a .54 RB has plenty of " Whompability", based on all the statements of members here on that score.

No disagreement here.

But what about this scenario: I own a .50 GPR that produces its best accuracy with a ticking patched .490" ball and 90 to 110gr of 2F Goex. The accuracy is outstanding; quarter, or sometimes nickle, sized 5-shot groups of the bags at 50yds . Any lighter charge of 2F Goex, from 80gr down to 40gr and the groups open notably (although still accurate for hunting). Why would I hunt with a lighter charge when my rifle produces such fine accuracy from 90gr of 2F up to Lyman's listed maximum of 110gr 2f? Do I need such a heavy powder charge for whitetail at the short ranges I hunt? ...Of course not, but that charge range is my rifle's sweet spot. It was a disappointment, actually, since I didn't intend that rifle for hunting and such heavy powder charges are useless to me for informal target shooting. When time permits I'll keep working on an accurate, but lighter, load.

If another finds his rifle to be more accurate with heavier powder charges, as I have, is he ill-guided in using that "heavy" load for hunting? If it is his most accurate load? To that hunter I say "damn the powder horn, let the sparks fly!"

 

[Swampman]

Why use 2F?

 

[HardBall]

Why use 2F?

2F will give less pressure than 3F for the same velocity earned even though it takes more of it. Lyman's 2nd edition BP loading manual illustrates this.

In this regard BP rifles are not unlike smokeless rounds; it will take more of a slower burning powder to equal the velocity of a faster burning powder but it will be done with less pressure. ...Or, a slower burning powder will exceed the velocity of a faster powder at the same pressure level. ...all things being equal.

And because I have much more 2F on hand and am trying to stretch my last pound of 3F before I buy more powder.

 

[Swampman]

I gave up on 2F years ago. Using less powder to get the same velocity, and much faster clean-up were the deal breakers.

 

[shmrck1]

Mark,
Ditto! I use nothing but 3fff goex...from
.32 to .54.Also as prime in my .50cal Lyman
GPR F/L.As I have stated in prior threads,I am
a hunter not a clover paper shooter.My criteria
for shooting may differ from some...
snake-eyes :hmm:

 

[HardBall]

I gave up on 2F years ago. Using less powder to get the same velocity, and much faster clean-up were the deal breakers.

I've never used heavy charges of 3F, preferring 3F for milder target/plinking loads and 2F for anything heavier. It may indeed burn cleaner.

Once I discovered God's personal favorite BP solvent, Ballistol, cleanup has become a non-issue, for me. I've been using a 1:1 ratio of Ballistol and Water (recommend on the can of Ballistol itself but a weaker ratio may work just as well) as both a patch lube and cleaning solvent. With a snug fitting patch/ball combo, I don't need to wipe between shots and final cleanup only takes a few Ballistol/water saturated patches. ...even with such heavy loads of 2F. Cleaning the patent breach takes a few more saturated patches wrapped around a breach brush.

Lehigh Valley lube also allows shooting heavy loads of 2F without wiping, in my rifle. I still use Ballistol and Water for final cleanup though.

The trick, for me, was a tight fitting patch. It seamed that a looser patch/ball combo didn't swipe as much gunk out with each shot, whereas a tight fitting combo did. This tight patch/ball combo is useless in the field though. I have to use a solid brass range rod with a ball grip on the end to load this combo. If I were hunting with this rifle I'd use thinner patching for ease of loading and not worry if it shot clean.

 

[Swampman]

Ballistol is petroleum based. I wouldn't use it. 3F is all anyone needs for any application short of a cannon.

 

[HardBall]

Ballistol is petroleum based. I wouldn't use it.

Mark, Ballistol is not petroleum based

 

[Swampman]

Of course it is. Read the MSDS.

 

[MikeChapin]

Ballistol is petroleum based. I wouldn't use it.

Mark, Ballistol is not petroleum based

It is mineral oil. It is petroleum based but all the stuff that turns to asphalt when you fire the rifle has been refined out of it.

There are a lot of things that get their start as petroleum. Not all are bad.

 

[Swampman]

Maybe good, maybe bad.
http://en.wikipedia.org/wiki/Mineral_oil

 

[renovato]

Ballistol is petroleum based, but it doesn't gunk up like many other petroleum products. It has been specifically designed so that it doesn't. I use it almost exclusively in all my muzzle loaders and quite a few modern guns too.

 

[Zonie]

As many of you may recall, I did several tests concerning black powder and oils effects on fouling.
In the second set of tests (page down in the link) the tests were run with Pyrodex and I added Ballistol to the types of oils being tested.

Follow this link if you want to read more about all of the tests:
OIL & BLACKPOWDER FOULING

For those who don't want to follow the link, Ballistol and Pyrodex did not form any fouling that was difficult to clean up.
How it acts with real black powder wasn't tested but the Pyrodex tests indicate that it may not be a problem.

 

[playfarmers]

Ballistol is the best stuff I have ever used. My load is 80-90g of 3f, felt wad and a patched .535 ball, and clean up is quick.