What is meant by gas checked hardcast

Gas checks others have covered well here, but hardcast is lead that's not soft. This is my opinion, there's no set hardness that makes something hardcast or not hardcast, but a bullet is hardcast to me if it's very difficult to put an indent into it with my thumbnail. If I can indent the bullet easily with my thumbnail, it's soft and not hard.

Harder cast bullets can be shot at higher veolocities and not lead the barrel, the gas check keeps hot gasses from touching the lead and causing it to lead the bore and because the gas check is brass/copper, it's going to take the heat and friction, without causing pressure issues being too hard to push down the bore itself.

I don't shoot hardcast/gas checked stuff often, but am planning to with a 125 grain .327 bullet for my Henry that I'm projecting will hit 2000 fps.
 
Hard cast is just hard relative to the old black powder bullets that were either pure lead or a low antimony or tin alloy. As others have mentioned, there is no exact hardness number above which it is defined, but I would say you don't usually see bullets of BHN 11 or lower called hard cast, nor bullets of BHN 16 and up not called hard cast. How in between hardnesses are labeled probably varies with the source.

I have never seen evidence of bullet metal melting. I see gas cutting that results in impact splatter plating the bore and dusting the ground in front of the firing point. Heat takes time to travel into a surface, and since the bullet metal is much more highly heat conductive than the gasses made by the powder, a temperature gradient in the gas will exist at the bullet surface so the bullet never sees the full temperature of the gas before it has left the muzzle.
 
Coated lead bullets are pretty new

The gas check was a way to deal with the isuse Uncleinick mentioned (that is new to me as well but gas check stopped lead issues, did not know what the mechanism is, good info but as often is true, if you avoid it consistently that is what counts!

I have 9mm lead bullets that have 3 grease groves.

This is an interesting read. I do have some of their bullets and no issues in 9mm. The grease does smoke some, I think coated are probably better but no experience.

http://www.pennbullets.com/unique.html

http://www.pennbullets.com/ReloadingTips/ReloadingTips.htm

Keep in mind, hard is just one aspect of a metal, there are all sorts of added elements as well ash how the metal is processed that end in various characteristics.
 
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Keep in mind, hard is just one aspect of a metal, there are all sorts of added elements as well ash how the metal is processed that end in various characteristics.
Click to expand...
Nebulus statement. Arsenic allows for the heat treatment (hardening) of lead alloys. There are several other metals that can be added, Copper for instance, but your statement seems more apropos to steels (where "toughness" and abrasion resistance, etc.) than lead alloys. Most readers here are only interested in the characteristics of lead alloys.
https://www.artfulbullet.com/index.php?threads/the-four-primary-metals-in-cast-bullet-alloys.59/
 
You can make lead hard and brittle, or you can make it hard and resilient.

Metal is metal though steel of course works in higher temp range and you can do within with it you can't do with lead.

How you cool it (how fast or slow ) can have affects as well.
 
I shoot a lot of cast. Everything from 900 fps subsonics up to 1700 fps from my 460 XVR handgun. No gas checks required <1400 fps. Once I get above 1100 fps I use poly "wads" that sit against the base of the bullet. The wads protect the base of the bullet from becoming "gas cutted" Gas cutting is when the hot gasses melt and distort the base causing accuracy issues or barrel leading. Gas checks are the best method of maintaining bullet base integrity from higher velocities. At some point after I gain some more experience I plan on casting and shooting "hard" cast for my 8mm Mauser and those will be up around 2000 fps, which obviously will require a gas check.
 
The P-wads Road Clam mentioned were another of the late Roger Johnston's contributions (NECO), AFAIK. At least, NECO was the first to offer them commercially and tools to start them into case necks ahead of bullets. I always cut my own from 0.060" LDPE sheet material with punches I made. They are effective because they are soft enough to bump up even at pressures too low to upset a lead bullet, so they seal well and they tend to lubricate the bore.

I just realized I never move this to the casting forum. Doing it now.
 
I cast a 390 grain bullet for my 1895 Marlin. Biggest cause of leading is not velocity but the bullet being a correct fit for the barrel. Mine slugs out .458.2. My mold cast a.461 bullet that I size to .459. Around 1100-1200 fps I don't need the gas check but I'm running around 1500 fps and prefer the gas check in either situation to prevent blow by of gasses. I get practically no leading. After 50-60 rounds at the range a bore snake with a little clp ran through about 3 times and it's clean. 45-70 a very old cartridge that is here to stay. I do water quench mine and the ones I have air cooled are around 18 BHN verses the water quenched being around 23-24 BHN.
 
I worked up a 300 grain SWC load in .44 Magnum When I added gas checks, the reduction in lead left in the grooves dropped substantially but I had to drop the charge by .3 grains to refind my tightest group size. If I ever go back to .44 Magnum, I'm going back to gas checks.
 
Howland, I'm with you. I shot some 285 grain out of my henry and a gas check made all the difference with leading. I'm water quenching and pushing the 285 around 1700 fps with full house load of h110. Hope to get a deer this year with it.
 
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