Found this 9mm Luger ammo vs 9mm

[Rick W.]

Over the years, I have often wondered about the SAAMI organization and its functions in the states. Is it a mandate or a suggested set of data?

I knew it was a dimensional reference to try to commonalize ammo and chambers here. Guess some definition for the industry needs to be in order to have interchangeable ammo and firearms(chambers) and to veer off such is a financial/physical risk. The wrath of a shooter that cannot chamber a cartridge in his weapon is a force to be reckoned with huh?; much less one that got hurt and the litigation that follows for years.

The circled X to me has always been just a dimensional identifier, nothing else. The numbers tell the story. Not a M.E. here.

The 754-776 is the go and no go chamber dimensions, take a reading on your gages. Interesting to note that a case can be 744, and in a max chamber of 776, looks like some stress is put directly on the extractor. A lot of once fired brass is shorter than the 754 number, probably for edge in commonality.

Some gunsmiths will chamber a minimum chamber, trying to help out the fit of case with today's brass. Some will give more slack, and comes down to philosophies. Combat weapons need to go no matter what, competition guns that need the accuracy; get the tighter fitment.

I now remember Mark1 talking about other standards for the min/max of the 9mm. The numbers he mentioned pretty much are like what most smiths will chamber a new 9mm barrel to in final breeching. Tighter numbers.

When I first got into reloading, we all rolled crimped. Revolvers got a heavy crimp, autos got a light crimp; since we all knew how things headspaced right? Then the advent of the taper crimp available dies, and now even the collet crimp. So some advancements have been found over the years.

Of course, our friends across the big pond have their own version of a controlling or voluntary mechanism. With all the pictures I have looked at of vintage chambers in 9mm(thanks to all here) I have not learned enough yet about their dimensional data; maybe some day, but for now..........I have to live with today's brass dimensional data.