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Author Topic: starting and max load differences between lead and jacketed ??  (Read 846 times)

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Offline Scibaer

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starting and max load differences between lead and jacketed ??
« on: November 27, 2012, 12:31:14 PM »
as i read thru my loading manual, i see some major differences in the starting and , or max loads when it comes to a lead or jacketed bullet.
the same weight bullet, and other components and the max safe pressure, but the start load between a lead and a jacketed bullet can in some cases, be double.
why ? what dont i understand ?
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Offline Catfish

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Re: starting and max load differences between lead and jacketed ??
« Reply #1 on: November 27, 2012, 12:56:10 PM »
Lead is softer than copper and is easier to push it down the barrel so presure is lower.
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Offline wncchester

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Re: starting and max load differences between lead and jacketed ??
« Reply #2 on: November 27, 2012, 01:08:02 PM »
THAT, plus lead bullets can't take the speeds/acceleration of jacketed bullets without stripping off the rifling.
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Offline Scibaer

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Re: starting and max load differences between lead and jacketed ??
« Reply #3 on: December 06, 2012, 03:48:04 AM »
thanks for the replies. im doing some reading and getting a good understanding for pressures, speeds and the dynamics of how this all fits together.  im sure i will have more questions in the future.
 
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Offline mdi

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Re: starting and max load differences between lead and jacketed ??
« Reply #4 on: December 07, 2012, 10:45:48 AM »
Two very different types of bullets. Different metal in contact with the barrel, with very different charactics. Only thing in common is they are both bullets...
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Offline Ron T.

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Re: starting and max load differences between lead and jacketed ??
« Reply #5 on: December 09, 2012, 12:23:30 AM »
And as the amount and type of powder used to increase muzzle velocity, the powder burns HOTTER thus MELTING the back of the soft lead bullet... not a fun thing to have happen to your favorite firearm.  To eliminate this "melting", copper half jackets "cups" can be put onto the rear of the bullets to shield the soft lead from the hot flames of the burning  powder.

I did quite a bit of shooting with my Ruger Super BlackHawk single action revolver loading 10.0 grains of Herco (28 gauge shotgun powder)... but I used #2 alloy (aka "hard") cast bullet which didn't need a half-jacket as long as I kept the velocity below 1,000 fps... i.e., a low velocity "target" load for a .44 magnum much like the velocity of a .44 Special.  Incidentally, this load is extremely accurate when loaded into .44 magnum cartridge cases for use in a revolver.

I've seen half-jackets put on handgun bullets, but I've never seen half jackets put on rifle bullets.  I'm not saying it couldn't be done, it's just that I've never seen it done.


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Offline painted horse

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Re: starting and max load differences between lead and jacketed ??
« Reply #6 on: December 20, 2012, 05:54:24 PM »
If your question is just to satisfy your curiosity between the two (cast vs jacketed loadings) then the above answers are good. If on the other hand you're looking for information on the USE of cast bullets vs jacketed take a gander over at Cast Bullets...you'll learn how to push cast bullets well beyond 1000fps (in handguns) and 2000fps (in rifles) without leading and with stellar accuracy... 8)
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Offline Hairy Chest

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Re: starting and max load differences between lead and jacketed ??
« Reply #7 on: December 21, 2012, 07:23:03 AM »
Quote from: painted horse on December 20, 2012, 05:54:24 PM
If your question is just to satisfy your curiosity between the two (cast vs jacketed loadings) then the above answers are good. If on the other hand you're looking for information on the USE of cast bullets vs jacketed take a gander over at Cast Bullets...you'll learn how to push cast bullets well beyond 1000fps (in handguns) and 2000fps (in rifles) without leading and with stellar accuracy... 8)

Are you a Boolit Bub?  :D
 
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Offline Scibaer

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Re: starting and max load differences between lead and jacketed ??
« Reply #8 on: December 26, 2012, 07:46:17 AM »
i am reading richard lee's reloading manual. the section about bullet constuction, and speed and construction has gotten my attention.
 im trying to understand the differences between max pressures , lead vs jacketed against the max pressure of the firearm and how much the bulllet can take before it no longer works as designed.
 
one thing lee says in the book, is that there is a max pressure the bullet can take , based on the BHN.
 and he has a formula along with a table for figuring that out..
   by his standard a BHN of 15 is less then half of whats available for a 44 mag with a max pressure load at 36,000 psi.
  so either i dont understand, he is wrong or the 44 mag loads in my maunal are 2x what they actually should be or the real max pressure of a 44 mag is 19,000 not 36,000 psi ..
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Offline Hairy Chest

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Re: starting and max load differences between lead and jacketed ??
« Reply #9 on: December 26, 2012, 08:08:59 AM »
Quote from: Scibaer on December 26, 2012, 07:46:17 AM
i am reading richard lee's reloading manual. the section about bullet constuction, and speed and construction has gotten my attention.
 im trying to understand the differences between max pressures , lead vs jacketed against the max pressure of the firearm and how much the bulllet can take before it no longer works as designed.
 
one thing lee says in the book, is that there is a max pressure the bullet can take , based on the BHN.
 and he has a formula along with a table for figuring that out..
   by his standard a BHN of 15 is less then half of whats available for a 44 mag with a max pressure load at 36,000 psi.
  so either i dont understand, he is wrong or the 44 mag loads in my maunal are 2x what they actually should be or the real max pressure of a 44 mag is 19,000 not 36,000 psi ..

Maybe he means with his lube. 
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Offline painted horse

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Re: starting and max load differences between lead and jacketed ??
« Reply #10 on: January 03, 2013, 05:26:47 PM »
Quote from: Scibaer on December 26, 2012, 07:46:17 AM
i am reading richard lee's reloading manual. the section about bullet constuction, and speed and construction has gotten my attention.
 im trying to understand the differences between max pressures , lead vs jacketed against the max pressure of the firearm and how much the bulllet can take before it no longer works as designed.
 
one thing lee says in the book, is that there is a max pressure the bullet can take , based on the BHN.
 and he has a formula along with a table for figuring that out..
 
 
 

 
Weeeell, not saying Mr Lee's formula is without merit (have a copy of it posted in my reloading room) but, well, it's just, how can I say this, WRONG....as I alluded to in my previous post, there are answers to how to shoot accurate, high velocity cast bullets without leading the bore or have catastrophic bullet failure, and they don't have to be made from Kryptonite either....it's about the gun having proper dimensions and the bullets sized to fit....thats the short version....
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