Question and this is the only place it might fit

[milsurpaddict]

This is a question I asked in one of my Facebook fourms. Any help with understanding this would be appreciated

So another question. I like to see all the different answers. Lee second editions reloading manual list 9mm Luger/parabellum Case length at .754 and describes it as max trim length but all my 9mm brass not trimmed or touched measures out at .734. So the question is why is manufactured non trimmed brass shorter than what the load manual calls max trim length. These measurement are also listed in the Lyman reloading manual.

[Wolfer]

Max trim length is exactly that. The maximum that will fit in minimum spec chamber. Shorter is ok. Longer than max is ok if your chamber is cut long.

[GrayTech]

If it was MIN trim length you would have a problem.

[Omega]

The difference between minimum and max trim length, .754 is max, - .010 should be minimum, so if I understand it right .744 is minimum trim length though a little shorter would be ok as long as it still holds the pill in place.

Edit: Man I type slow.

[milsurpaddict]

So let me see if I get this correct
max trim length is not the shortest a case can be trimmed to
it refers to the longest a case can be to work properly in most guns

[Omega]

So let me see if I get this correct
max trim length is not the shortest a case can be trimmed to
it refers to the longest a case can be to work properly in most gunsYup, if you ever have a question on specs just lookup the saami drawing, it gives the min/max of all critical measurements.

[jcren]

This is very common with straight wall cases. I started with 38 special and bought 1000 range pickups. I don't think more than 5 of them measured max length, most were .010-.025 short. Liked to drove me nuts.

[MtGun44]

Why not put this in the handgun section?

[country gent]

The major reason why max length is longer than factory new brass is that as brass cases are fired and loaded the brass slowly flows forward from te case head to the mouth. Pressure, resizzing belling crimping forces all contribute to this effect. In real life brass grows in length due to use. .754 iss max thats what the brass can grow to thru use, then it needs to be trimed to bring back to specs this is .744 or .010 under. Want to prove it to yourself take a press, powder, primers, measure, dies, bullets and load the same 5 cases over and over checking length after every sizing.