New One Had Never Seen Before

[Bama]

First of all I seat gas checks with a home made in line seater. Check goes in bottom, bullet in top and top punch from top seats check with a couple of hits from hammer. Checks are in line and normally fully seated. After going through base sizer (push through) they are powder coated. Bullets today were cast in a relatively new mold. A number of gas checks popped off even though checks and bullets were dried under outlet of dehumidifier and preheated before check application to eliminate moisture as an issue. I had originally though it was a perfect fit between top lip of check and bottom of first driving band. Found that top of check was actually resting against bottom side of driving band instead of base of bullet. Just another thing to check. Checks were factory and mold was Lee.

[Dusty Bannister]

I had a problem with short gas check shank on a SAECO mold once. Not the problem with checks, but the way the mold was cut. Caliber and measurements?

http://castboolits.gunloads.com/showthread.php?11997-Gas-Checks-vs-Shank-Size

You might want to take a look at the chart for gas check dimensions further down in that thread. That should make clear if it is the mold or the check that is out of spec.

[gpidaho]

Bama; Your comment about making sure there was no moisture under the checks reminded me of one of my early powder coating screw-ups. I heat treated a batch of bullets in the normal fashion and some time later decided to powder coat them. As the bullets came up to temp it was like popcorn in the oven. lol Gp

[Oklahoma Rebel]

what makes them do that? just curious!

[Bama]

If any moisture is present, it will turn to steam which requires a very large additional volume. Also it there is very much volume between gas check and the base the heated air expands, builds pressure and blows the check off. I didn't realize what a mess it made with close packed 200 gr 30 cal--when one falls over a large portion of them go over--PC sticks them together.

[Shiloh]

I have a disc made from .163 steel that fits in the well of the Lyman lube die. With the seater in place, I can seat stubborn checks. Seats them dead straight and flush with the bottom of the boolit. I lube in a separate step. Particularly with 8mm. My .30's don't need it.

SHiloh

[tankgunner59]

I use Lee equipment and Hornady gas checks. I PC then crimp on the GC when I sizethe boolit. I haven't had one come off in firing yet.