At what velocity does leading occur...Caliber specific?


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goathollow
December 10, 2012, 06:08 PM
Up to what velocity can you shoot cast lead bullets before leading occurs?

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243winxb
December 10, 2012, 06:12 PM
2200 fps

bluetopper
December 10, 2012, 06:32 PM
Depends upon bullet fit in the barrel, bullet hardness, and if the bullet is gas checked or not.......among other variables I would imagine.

I have shot 350gr 500 S&W Mag hard cast gas check bullets at just under 2200fps with no leading whatsoever.

Arkansas Paul
December 10, 2012, 06:39 PM
Depends upon bullet fit in the barrel, bullet hardness, and if the bullet is gas checked or not.......among other variables I would imagine.

Yep. There's no set in stone number. There are several variables at play. In addition to the ones parasite listed, proper lubrication could also play a factor. I'm sure there's more.

I think that too hard a bullet at too low a velocity can produce leading as well. Someone correct me if I'm wrong on that, but I think I read that on the castboolits site.

zxcvbob
December 10, 2012, 06:40 PM
It depends on the gun. I have a Ruger Blackhawk in .30 Carbine that I've shot plain-based cast bullets at over 1700 fps without leading -- it's hard to believe. OTOH I have a Taurus Gaucho .357 that leads badly with everything, .357 or .38 Special. (I should fire-lap the Taurus; it couldn't hurt anything)

DeadFlies
December 10, 2012, 06:53 PM
It depends on the hardness of the bullets, its fit into the barrel and the pressure (NOT velocity) it is being subjected to. Lee goes on at great length about this in Modern Reloading.

ranger335v
December 10, 2012, 06:57 PM
I've never tested such an idea but I'm quite sure we can get leading if we slowly push an improper bullet down any caliber bore with a ramrod.

Sam1911
December 10, 2012, 07:09 PM
Brad over at Missouri Bullet Co. has a good write up on the formula on his web site: http://www.missouribullet.com/technical.php

Duckdog
December 10, 2012, 07:35 PM
I think Lee hit the nail on the head in regards to pressure, not hardness. I have messed with his loads and formulas and they seem to be pretty good.

As said, there is nothing set in stone. Makes it fun.

bds
December 10, 2012, 10:54 PM
Up to what velocity can you shoot cast lead bullets before leading occurs?

There are many factors that contribute to leading - http://www.lasc.us/Fryxell_Book_Chapter_7_Leading.htm

Leading caused by the bullet.

The cause of leading can be traced to the bullet if it's the wrong hardness for the application, the wrong size for that particular gun or a plain base design in an application that calls for a gas-check. As discussed above, too soft of a bullet (e.g. BHN < 8) can be stripped if pushed too fast, while a bullet that's too hard (e.g. BHN 22) can fail to obturate, and lead the trailing edge of the lands. This is a common problem with commercial hardcast bullets pushed at intermediate velocities. The bullet can also be the source of leading if it is sized too large (lead build up in the forcing cone) or too small (coated over the entire bore). The bullet can also be the cause of leading if the sixgunner is using a PB bullet in a load that generates more than about 40,000 psi peak pressure or 1500 fps muzzle velocity; these applications are better served by GC bullet designs.

goathollow
December 10, 2012, 11:33 PM
There are many factors that contribute to leading - http://www.lasc.us/Fryxell_Book_Chapter_7_Leading.htm
Well that pretty well covers it, thanks!

What I failed to mention is I am shooting a .460 out of a 20" barrel encore rifle. I'm not sure it's worth the time, effort or cost to find a cast lead load that will run slow enough to not lead up the barrel. I can just stick with jacketed bullets and shoot something else for fun.

Sam1911
December 11, 2012, 06:46 AM
.460 will prove a challenge if you're sticking to "true" .460 loads. You certainly could use Trail Boss to make a load for a big 350+ grain lead bullet that wouldn't lead, or use any number of .45 Colt loads, but those are all pretty reduced compared to the real magnum charges.

But, they'd be a whole lot of fun to shoot and plenty for deer hunting or other light-duty uses.

evan price
December 11, 2012, 07:10 AM
It depends. Bullet size versus true bore size versus forcing cone size. Lube choice. Hardness (or softness) of the alloy. Powder burn temperature. Style of rifling. Smoothness of barrel, forcing cone and leade. Crimp style and amount.

You can have one gun that shoots cast perfect then put that exact same bullet in an identical gun and get leading.

homatok
December 11, 2012, 03:08 PM
For the large calibers, I would: slug the bore, size the cast bullet to 0.001/0.0015 larger than bore size and use an alloy of 50/50 wheel weights and pure lead. I would heat treat or water drop the bullets out of the mould and then do a lot of reading, following which i would choose an appropriate powder and start low and work up. Bullet FIT IS KING! Have fun.

bluetopper
December 12, 2012, 08:04 PM
I'll just say.......I shoot cast lead bullets in all my handguns and one rifle and get no leading whatsoever. From 38 Spl, 357 Mag, 9mm, 44 Magnum, 45acp, and a 500 S&W Magnum rifle.

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