New Gas Checks VS Old Gas Checks ??

[cwheel]

Found myself in need of a fresh reloading manual, all of mine are at least 15 years old. I choose the Lyman 49th edition and just got it here and started reading. I choose the Lyman because of the cast data listings in it that are often overlooked by others. On page 84 they talk about not using any old press on gas checks when the boolit is seated blow the case neck. Is there a difference between old gas checks and the new ones ?? Casted and sized a small run of 38-55
265 gr. and when sizing to .381, I installed gas checks that might be older than I am. Lyman brand and for .375 cal. With the 38-55, gas checks below the case neck won't be a issue, no neck to the case. But this takes me to the question if there is a difference between new and old. So far I've been using another old box of gas checks on 30-30, and if it holds true, it might matter with that one. Give you a idea how old the 38-55 gas checks are, price on the box is $3.25. Thanks,
Chris

[338RemUltraMag]

When using a press on check (like my aluminum ones) as long as you can not pull them off with your fingers when crimped they will be just fine.

[cwheel]

Kinda thought that would be the case, if it fits and stays, good to go. Thanks,
Chris

[Smokin7mm]

The concern here would be with the older gas check (non crimp on) if you seat the bullet below the neck you would risk the check falling off inside the case. If it is a straight wall case (no neck) no problems. Most newer style checks are crimp on. The other issue with seating below the neck is you are exposing the lead on the side of the bullet to the hot powder gases which can cause leading issues. When using any gas check in a bottle neck case I make it a practice to never seat below the neck.
Bret

[338RemUltraMag]

That is a good practice, BUT there is one exemption to that, if your boolit base is seated below the neck and is compressing the powder charge you will be just fine.