The Shooters Box case and ammunition gauges are manufactured right here in Malden Massachusetts, by American workers on American machines! 

Made from T6 6061 Aircraft Grade Aluminum, beautifully anodized in red color and built to last a lifetime.  Each gauge is manufactured to S.A.A.M.I (Sporting Arms and Ammunition Manufacturers Institute) minimum chamber / headspace specifications.  The gauge will measure the maximum cartridge length (full overall length), the minimum and maximum case length, and the maximum case diameter.

A loaded cartridge should fit freely and easily into the gauge.  A cartridge that does fit properly may not correspond to the proper chamber dimensions. 

Place a clean cartridge into the gauge and make sure that it is completely seats by itself with no assistance to seat it.  The head of the bras should sit flush within the lower or upper step of the gauge.  If the cartridge sits higher than the upper step then your brass might be too long.  It's easy to check by eye or with the help of a straight edge or steel rule.  With the cartridge in the gauge check the backside to make sure the tip (bullet end) is not protruding outside the back face of the gauge.  If the tip of the bullet protrudes from the end of the gauge it is longer than the maximum allowed cartridge length.  It is If the cartridge does not easily drop into the gauge without assistance there is most likely something wrong with the dimensions of your cartridge.  A cartridge that will not easily fit into the gauge may or may not fit the chamber of your barrel.

Complete satisfaction guaranteed.  If for any reason you are not satisfied with this product please contact us at 781-321-9899. 

WARNING!!!  NEVER ATTEMPT TO RESIZE LOADED CARTRIDGES.  THIS IS EXTREMELY DANGEROUS AND COULD LEAD TO AN ACCIDENTAL DISCHARGE CAUSING INJURY OR DEATH.

In some instances your cartridge may sit flush with the lower step BUT the brass may be shorter than the SAAMI minimum specifications.  In this instance your ammunition may still fire and function correctly but it is up to you to confirm this will not cause an unsafe condition.  It is the reloaders responsibility to determine the cause of incorrectly sized cartridges and to correct it.  In some cases ammunition previously fired with maximum powder loads or with abnormally large barrel chamber diameters may not fit this gauge.  This is due to some resizing dies not being able to fully resize the brass cartridge all the way down to it's head. Any ammunition shown in pictures is purely for representation purposes and is not included with the purchase of this gauge.