Gas checks with .40?

[WVfishguy]

I've got some .40 cal., 145 grain lead bullets. I think they are pretty soft.

All load data I've seen has light .40 S&W bullets exceeding 1,000 fps, so I'm concerned about barrel leading.

I've used gas checks on .38 cal. revolver loads. Can you use gas checks on semi-autos?

[SL1]

Yes, you can use gas checks in the .40 S&W, but maybe not for your bullets.

First, gas checks raise pressure. So, you would at least need to get some data for THAT bullet with gas checks on it. The .40 S&W cartridge has a SAAMI max pressure of 35,000 psi, and that is NOT enough to give obvious pressure signs so that you can look at fired brass and know when you are exceeding it. So, "start low and work up" doesn't really address what you want to do here.

Second, a bullet needs to be designed for gas checks to have them work well. If you try to press a gas check on a flat-based, soft-lead bullet, you will (1) distort the bullet base and hurt accuracy, and (2) probably not eliminate leading. The reason that leading probably would not be eliminated is that a properly designed gas-checked bullet has an open space between the last driving band and the gas check. That provides a place where the lead can be scraped-off the barrel and deposited by the gas check.

So, I suggest that you shoot your soft bullets at low velocity and then buy or cast some designed for gas checks if you want to shoot lead faster than you can without leading with those soft ones.

And, you can shoot lead from a .40S&W at less than 1000 fps. Also, your soft bullets may or may not actually lead significantly somewhat above (or below) 1000 fps.

SL1

[kraigwy]

First you bullet needs to be made to accept gas checks.

Then just because the bullet will take gas checks dosnt mean you need to use them. Some guns like gas checks, some don't. If you have a gas check bullet, try them both ways and see.

If the bullets are lubed right, you may not have leading problems with soft lead. Also there is no law that says you have to load any bullet, leat or not to max.

I loaded some 40 cal for my kid to shoot in his ICE issue pistol. I loaded them just fast enoght to work the action reliably. They shoot pretty good. Make good practice loads.