H&M Tool Co. .22 go-no go gauge set

I got it 'cause it is soooo cute. Any info will be appreciated. Does anyone actually use headspace .22 gauges?

22 RF headspace is just as important as it is on any rifle or handgun. The RF cartridge is relatively low pressure which can lull you into a false sense of safety and cause you to think that headspace is not important. But you have to remember that many 22 rifles and handguns are weak in design, which can result in a ruptered case head. That hot gas coming back at you is a lot faster than you can dodge. ;-) ;-)

That’s a very nice souvenir.


Vlad, nice set of gauges, thanks for sharing. The correct name of this company is H&M Tool Co. and was located in Farmington, Michigan.

Further to what Ray said, poor headspace of .22 even in strong rifles like Model 52 Winchesters and Winchester 1885 single shots can reduce accuracy. So, by the way, can weak firing pin strike.

We used to have not only a set of headspace gauges (I seem to recall they were supplied by the Army, as it was a High School ROTC rifle team), but we also have a gauge for maximum rim thickness. It was like putting the cartridge in a slide top box (like the 100 round boxes). If the slide did not pass freely over the head of the cartridge, then you could expect the bolt would not close properly. I had a “squeeze off” in my own rifle (Win Model 52C) due to strong bolt closing, and me forcing down over the cartridge. It was ammo the other team supplied, as we were short for the match. Our gauge was supplied by a friend of mine on the team (our best shot, by the way) but as I recall, we left it on the range. The other team’s coach wanted to call it my shot, until my coach thought to have me eject the fired case and saw there was no firing pin impression on it. Of course, when you have an unintentional discharge, even down range like mine went, on a supervised situation like kids in a shooting match, you don’t touch anything, including even ejecting the case, until you coach instructs you what to do.

Vlad, here is an ad published in 1957: