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**Aguila Blanca** · December 17, 2018, 02:48 PM

The Lyman gauge referred to is a cartridge gauge, not a case gauge. Its purpose is checking loaded ammunition against the SAAMI maximum cartridge dimensions. If your loaded rounds won't fit into the Lyman gauge, they are not within industry standards, regardless of whether or not they'll chamber in some (or even all) of your firearms.

Here's a link to the SAAMI specifications for centerfire handgun ammunition. .40 S&W is found on page 60. I would suggest that the next step would be to take several of your loaded rounds and check the dimensions against the SAAMI dimensions. Note that the dimensions shown for the cartridges are the maximum -- the tolerance is the stated dimension minus .008".

https://saami.org/wp-content/uploads...dR.pdf#page=60

Especially since you suspect that your cartridges may be out of round, take each measurement at three points around the perimeter to see if there is an out-of-round problem (possibly in combination with an oversize problem).

December 17, 2018, 02:48 PM	#18
Aguila Blanca Staff Join Date: September 25, 2008 Location: CONUS Posts: 18,476	The Lyman gauge referred to is a cartridge gauge, not a case gauge. Its purpose is checking loaded ammunition against the SAAMI maximum cartridge dimensions. If your loaded rounds won't fit into the Lyman gauge, they are not within industry standards, regardless of whether or not they'll chamber in some (or even all) of your firearms. Here's a link to the SAAMI specifications for centerfire handgun ammunition. .40 S&W is found on page 60. I would suggest that the next step would be to take several of your loaded rounds and check the dimensions against the SAAMI dimensions. Note that the dimensions shown for the cartridges are the maximum -- the tolerance is the stated dimension minus .008". https://saami.org/wp-content/uploads...dR.pdf#page=60 Especially since you suspect that your cartridges may be out of round, take each measurement at three points around the perimeter to see if there is an out-of-round problem (possibly in combination with an oversize problem).