Formula for Gas Check material thickness

[10x]

My thanks to

Motor is right on this. Aluminum checks work great if they are sized appropriately to fit your bullet. To determine the best thickness check for your bullet you need to do a little math.

T = (S_d - SH_d) / 2
T = Material thickness required.
S_d = The Bullet Final sized diameter
SH_d = The Bullet Gas Check Shank Diameter

Once you have that stickness you should be able to get checks that would fit perfect to your bullets. In my experience your probably looking for a 0.010 thickness check. Most aluminum checks out there on ebay are 0.0145 or similar.

This really useful formula should be a sticky in the Gas Checks forum

Some folks may want to add 0.001" to the check material if they want the check to go on tighter.

[elwood4884]

This formula will work with slip fit copper checks in addition to aluminum as well.