Lead bullet hardness

[opos]

Question about cast lead bullet hardness. I'm going to load 45acp with 200 grain LSWC bullets to a "mid range load" per the Hodgden charts of about 850fps. The bullets I want to use are available in 2 hardness ratings..one of 12 and one of 18. It seems to me that the harder alloy would lead to less leading (if any at this velocity) but I'm not sure about the hardness specs...Anyone have a fairly simple and straightforward way to determine which hardness to order..hate to get 500 bullets and find I've ordered the wrong thing. First time out on loading 45 LSWC for me. Thanks

[Ugly Dwarf]

I stole this from the Cast Boolits site HERE

The LASC Site referenced is found HERE.

Basically, they are saying that ideal hardness falls within a "window"... too hard or too soft and you will encounter problems.

Happy reading.

Dwarf

Form the LASC site:

Approximate "Maximum" Chamber Pressure For Lead Alloys (PSI)

Plumbers lead, stick on WW 13,000 - (Black Powder Only)
Wheel weights / clip-on 25,000 - Non-Magnum handgun
loads, Rifles to 1,800 fps
Lyman # 2 (alloy varies in
Lyman cast bullet books)
35,000 - Magnum handgun &
rifles to 2,000 fps
Quench-cast WW (dropped
from mould into cool water)
48,000 - Magnum handgun
& rifles to 2,200 fps
Oven heat treated WW 55,000 - Jacketed velocities in handguns
and rifles with quality bore & balanced load
-----------------------------------------------------------------------
Bullet BHN / "Minimum" Chamber Pressure For Lead Alloys (PSI)

The formula (from the pages of HandLoader Magazine) to determine at what pressure an alloy of given BHN will obturate the base of the bullet and seal the bore. If the bullet is too hard to obturate, gas cutting usually occurs on the base band on the non-driving side of the rifling and barrel leading is likely. Simply multiply the alloy BHN by 1,422.
Example: Alloy BHN of 12 multiplied by 1422 = 17,064. An alloy of 12 BHN should be used with a load that develops a "minimum" of 17,000 psi. Need more info on minimum / maximum alloy BHN? These Glen E. Fryxell articles explain alloy BHN in easy to understand language.

[bohoki]

hardness is an attempted fix for poor fit when it comes to pistols

[ZakAttackMan]

hardness is an attempted fix for poor fit when it comes to pistols

+1

Thats why slugging your barrel (sometimes chamber) and sizing is far more important than hardness.

[xrMike]

Cast bullets really should be "hardness-optimized," depending on how fast you're going to push them, in order to minimize leading (lead build-up) in the rifling of the barrel.

Think about it this way: When the powder goes off in the round, it needs to "deform" the base of the bullet enough so that it makes a good tight seal against the rifling. If the lead is too soft, it deforms too much and smears lead into the grooves of your rifling. If the lead is too hard, it doesn't deform at all and you get gas blow-by, poor contact with the rifling, and therefore poor accuracy.

Given the above info, you can see why you'd want a softer bullet for target velocities, and a harder bullet for IDPA and other shooting sports where you have to make "power factor," and therefore drive the bullet faster (with higher pressures).

It's explained better here: http://www.missouribullet.com/technical.php

[opos]

Cast bullets really should be "hardness-optimized," depending on how fast you're going to push them, in order to minimize leading (lead build-up) in the rifling of the barrel.

Think about it this way: When the powder goes off in the round, it needs to "deform" the base of the bullet enough so that it makes a good tight seal against the rifling. If the lead is too soft, it deforms too much and smears lead into the grooves of your rifling. If the lead is too hard, it doesn't deform at all and you get gas blow-by, poor contact with the rifling, and therefore poor accuracy.

Given the above info, you can see why you'd want a softer bullet for target velocities, and a harder bullet for IDPA and other shooting sports where you have to make "power factor," and therefore drive the bullet faster (with higher pressures).

It's explained better here: http://www.missouribullet.com/technical.php

Thanks and the Missouri bullet page really explains things concerning the basics of hardness and why harder isn't always better....don't even comment on that to an old man! The basic hardness calculation for the bullet/powder combination I'm interested in comes out to a number around 10.5 so a 12 hardness..which is what they suggest for a low velocity target load as the correct bullet.