Gas Checks

photo-8 Samples of copper .30 caliber gas checks I make from 1/2" x .012" coil.

I also make and sell .30 caliber, 6.5mm & 8mm caliber checks from copper & aluminium coil. 35/.357/.358 now available

Please check out the Gas check store for details. These samples were made with tools supplied by Charlie Darnall at freechex

 

The formula for coil material thickness you need is:

T = (S d  - SH d ) / 2

    T is material Thickness required
  SH d   is the bullets gas check Shank diameter
  S d  is the bullets final Sized diameter

 

 

 

The table below is for example only.  It was compiled from various charts and tables. There is a lot of conflicting data. The only way to get the proper sizes is to MEASURE YOUR BULLET WITH A MICROMETER!

CAL SHANK CHECK DIA DISC DIA SKIRT HT THICKNESS
.22/.24 .216 .232 .306 .045 .010
.243/6MM .234 .252 .344 .055 .010
.25/.257 .244 .264 .344 .045 .010
.264/6.5MM .254 .271 .364 .055 .010
.270/.277 .255 .268 .385 .065 .016
.284/7MM .250 .290 .370 .060 .016
.30/.308 .283 .320 .404 .060 .014
.32/8MM .304 .334 .404 .050 .014
.338 .330 .346 .450 .060 .010
.348 .321 .352 .431 .055 .014
.35/.357/358 .341 .360 .451 .055 .008-.010
.375 .356 .367 .456 .050 .014
.41 .395 .417 .525 .065 .010
.44 .404 .436 .508 .052 .016
.45 .428 .428 .532 .052 .016
.50P .458 .458 .578 .060 .020

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