lead bullet vs speed questions


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Cranky CJ
April 13, 2013, 01:26 AM
lead bullet hardness vs too fast of bullet speed = leading. yeah or nay?

For example if you have a 'softer' lead bullet, shooting it at a 'fast' rate, is leading connected to bullet speed and bullet hardness?

If NO, then what is leading connected to or caused by?

This to settle a disagreement.

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bluetopper
April 13, 2013, 01:36 AM
Ready to check out for the night and want to be brief, but bullet to barrel fit is much more critical than bullet hardness.

With a good #2 bullet alloy and a good bullet fit you should have NO leading in your barrel through top end 44 magnum and 357 magnum velocities.

Velocities above that you should use gas checks on the base of your cast bullets.

david_r
April 13, 2013, 01:40 AM
http://www.lasc.us/FryxellCommentsCBAlloys.htm

DooFighter
April 13, 2013, 01:40 AM
What do you consider a good fit? .001 over slugged size? .002? I've heard different answers on this...

Jesse Heywood
April 13, 2013, 02:01 AM
What do you consider a good fit?

On a semi-auto, most go with .001 over.

On a revolver, I try to match the cylinder bore, maybe a shade over. As much as .002 over the barrel. The forcing cone will squeeze the bullet down to the barrel size. The big thing is to start with a low load and work up.

For an example on how soft you can go in my 686. .358 dia. DEWC BHN 10, .357 mag cases. 6.0 gr. Unique, which lists 1,300-1,400 fps. Shot 100 rounds with little leading.

steve4102
April 13, 2013, 08:25 AM
I am new to casting and shooting lead bullets, so I do not know the answer to your question, but I do have an example of my experience.

My bullets are cast from straight WW, nothing else added, what BHN that is, I duno, but I have read it is on the soft side.

This is a photo of all the lead and other fouling that came out of my 10mm after 150 rounds. 170gr HP bullet sized to .401 tumble lubed with Lee Alox at 1200+fps. Is this a lot of leading, duno, you tell me.

http://i2.photobucket.com/albums/y17/steve4102/leadinbarrel_zpsbf348c25.jpg[/URL]

DooFighter
April 13, 2013, 09:09 AM
Steve, that looks like quite a bit to me, but I am also a novice when it comes to lead. I get similar results from my 6" 686 after 200ish rounds. Do you use a lewis lead remover?

I say it seems like a lot because lets say you did a real good job and removed 95% of the buildup. 5% remains, extrapolate that out over a couple thousand rounds, or more and it could really foul things up.

I was buying lead not casting it so I simply pay a little more and buy plated now. Must be a lot of casters in my area because wheel weights are hard to come by.

Sport45
April 13, 2013, 09:50 AM
I say it seems like a lot because lets say you did a real good job and removed 95% of the buildup. 5% remains, extrapolate that out over a couple thousand rounds, or more and it could really foul things up.


That's not how it works. If you don't get all the lead in your cleaning process you will leave about the same amount each time. It's not like you will always leave a little more in a perpetual accumulation.

It's like emptying a pickup load of dirt with a shovel. You get 99% out and leave some in the corners. After refilling the truck and unloading it again the same amount is left in the corners. After a year or three if the dirt in the corners really bothers you it can be swept or hosed out.

steve4102
April 13, 2013, 09:56 AM
That's all of it, everything, the barrel is perfectly clean.

No, I do not use the Lewis thingy. I use a nylon bore brush wrapped in Copper Chore-Boy.

Thompsoncustom
April 13, 2013, 10:39 AM
steve4102:

After your completely done reloading have you pulled a bullet and measured it to see if it was sized down at all? Also make sure your not using the Lee Factory Crimp die with lead bullets as 9/10 times that die will cause problems.

Also slug your bore as it's going to be impossible to know if your have a undersized/oversized bullet till you know what your barrel size is.

Cranky CJ:

Hardness can make a difference but like said above Fit is King and then comes Lube everything else doesn't matter so much unless your really pushing the limits.

243winxb
April 13, 2013, 11:24 AM
For example if you have a 'softer' lead bullet, shooting it at a 'fast' rate, is leading connected to bullet speed and bullet hardness?
Yes, Skidding/stripping may lead. If NO, then what is leading connected to or caused by? If lube & diameter are correct, high pressure may cause the alloy to fail. Cast bullets can be pushed at the same velocity, one will lead, one will not. Fast burn rates of powder will lead before slow burn rates. Example in 30-06 Unique VS IMR 4895, both may produce the same velocity, but the Unique will lead because of the high/short starting pressure curve. :)

bluetopper
April 13, 2013, 11:25 AM
Steve, what size sizer do you run your bullets through when you are lubing them?

I shoot commercial cast bullets that I mail order and have been for years in many different handgun calibers and I simply do not ever have a problem with my barrels leading at all.

243winxb
April 13, 2013, 11:33 AM
http://i338.photobucket.com/albums/n420/joe1944usa/Lee358-158-RF.jpg The one on the left was loaded over 17 grains of Lil' Gun. The one on the right was loaded over 13 grains of Lil'Gun. The one in the middle is not fired.If you exceed Lees Maximum pressure you will get Plastic deformation -------------------------------------------------------------------------------- http://castboolits.gunloads.com/showthread.php?p=35425#post35425 Quote: This whole relationship centers around the elastic limit for the alloy you are using and what the elastic limit is. the elastic limit is the point at which stresses can occur to an object and it will return to it's relative shape. Once you have reached the deformation stage it no longer returns to relative shape. this is a very simplified version of this topic as it pertains to engineering mechanics of materials. This is meant to be a guide and to keep you within safe/acceptable limits for pressure and alloy for your purposes. Obturated bullets do not mean that the shape has went through plastic deformation, just that it has expanded and stayed within the elastic limits of the alloy. The formula does not take into account other factors that aide in reducing friction and thus combined forces on the cast slug. As stated above, one member is getting very good accuracy with soft (by most peoples standards) alloys in high velocity loads (for cast anyway). Another factor not talked aobut is the pressure curve of the powder/cartridge combination. Does it spike quickly (fast pistol powder in rifle size case) or is it a gradual increase (full case of slower powder). Protection of the bullet base can also be a factor, we routinely do this by gas-checking, using lube wads, or fillers. http://en.wikipedia.org/wiki/Plasticity_(physics) plasticity describes the deformation of a material undergoing non-reversible changes of shape in response to applied forces Obturate means to block or obstruct.

Sam1911
April 13, 2013, 12:02 PM
Brad over at Missouri Bullet Co. has an interesting write-up on balancing the pressure of your load to the hardness of the bullet alloy for minimal leading.

http://www.missouribullet.com/technical.php

You'll see that he offers bullets at several hardness levels intended for various pressure ranges from mild to wild.

mdi
April 13, 2013, 02:05 PM
A bullet that won't seal the bore, no matter how hard/soft it is, will lead the barrel. Most leading is caused bu hot gasses bypassing the base and melting the bullet's sides and depositing lead on the barrel. I have shot lead bullets (approx. BHN of 10-12) to magnum velocities in my .357 and .44 Magnums. The .357 Magnum cylinder throats measured .358"+ (mebbe .3585") and I sized the bullets to .358"+. Groove diameter was .357". Same scenario with the .44s, sized same size as cylinder throats which is .002" over groove diameter. For my semi-autos I size .002" over groove diameter (45 ACP gets .452" and 9mm gets .358")...

Hondo 60
April 13, 2013, 11:06 PM
http://www.missouribullet.com/technical.php

Use this link to get a very easy to understand article on bullet "hardness".
But this is only one aspect that can cause leading.
As others have said, bullet to barrel fit is the other aspect.

Cranky CJ
April 14, 2013, 11:25 AM
It appears I was in error. Now I'm better informed. Thanks everybody.

fecmech
April 14, 2013, 08:58 PM
Fit is most important. Sized to the throat in a revolver or maybe .001" over and at least .001-.002" over groove size in a fixed breach gun. You can shoot very soft bullets to high velocities in pistols with no leading at all with decent lube and good fit. Accuracy is another story. Softer bullets will slump from acceleration and accuracy suffers.

Reefinmike
April 15, 2013, 01:15 AM
Im fighting a leading problem and am baffled and may switch powders. Im using an alloy of ~70% clip on wheel weights and about 30% pure(ish) lead. This week I casted up 200 158gr lswc. 100 of which I let air cool(softer) and 100 quenched in water(harder). I then took 50 of each set and sized them down from .360 to .358. so essentially i had 50 of each quenched sized, quenched unsized, air cooled sized, air cooled unsized and for each of the four groups, I loaded up 16-17 of each 3.4, 3.7 and 4.0gr of HP-38. The 4.0gr loads across the board leaded the bore fast. The other loads were pretty good to the bore but during this experiment, the one thing I noticed is that the bullets sized down were significantly more accurate than the unsized bullets.

Im still frustrated by this leading problem which seems to have happened all the sudden with my standard go to load (3.4gr hp83 with a quenched and sized boolit). another issue I was trying to fix has not been resolved, even with a load over the "max" listed in the lee book- Im still getting soot along the casings leaving perfect "shadows" of the casings back along the breech face.

My leading problem is causing me to loose sleep... all the sudden, the last two batches of the 3,000 some rounds of my go to load are slicking the bore in PB... cylinder lockup is still tight and gap still at about .005"

Should I add- If any leading doctor is reading this, I believe my situation is unique as im seeing shiny lead spattered over the leading edge of the forcing cone which meets up with the cylinder face.

243winxb
April 15, 2013, 08:29 AM
Add Linotype, air cool, size/lube.

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