Case Trim Length Question

[Grandpawmoses]

Seeking some advice from the people who know. Usually I've found that different manuals pretty much agree on case trim length.
I just started to reload the .40 S&W and it seems that the case trim length varies by the different reloading manuals. One manual says 0.845 but another says 0.840. My question is, what's considered too short?

 

[Cemetery21]

Maybe I'm not the person that knows: I've loaded/shot pistol ammo since the mid 1970s. I've never trimmed pistol brass. Further, I've never looked at the manual trim length or even measured a pistol case.
If I was loading heavy revolver rounds and wanted a consistent heavy roll crimp, I might consider trimming. But a 40 and most semi-auto brass gets taper crimped so the case length is not critical. I believe it gets shorter with firings (unlike bottleneck brass), so it's probably short after a while anyway.

 

[Grandpawmoses]

The reason I ask is I was given some miscellaneous range pick-up brass and the lengths varied. Not much but I thought I'd like to make them all the same length.

 

[Bill K]

Same with me, never had trimmed those type of handgun cases, as most headspace on the rim. Unless they just will not chamber nicely, upon reloading, I would not worry about trimming them. Follow procedures on reloading handgun ammo ( Straight cases) and shoot them.

 

[GWY]

Agree with previous posts. Never trimmed for any pistol calibers I reloaded

 

[tsyarnall]

SAAMI max is .850” so anything that length or less is good to go. As far as too short. I, myself, try to stay as close to the max as I can, while maintaining across the board consistency with all my cases for that round.

 

[dellet]

With .40 it can be worthwhile trim or at least check range brass. You can get stuff with the famous Glock belly or that has had that and been resized.

Glock’s leave the base of the case unsupported and when fired bulge on one side. They are sized backwards to get rid of the bulge before being ran through a regular sizing die. You often end up with a case with an uneven neck. Plays hell on headspace and accuracy.

 

[EOD Rob]

With .40 it can be worthwhile trim or at least check range brass. You can get stuff with the famous Glock belly or that has had that and been resized.

Glock’s leave the base of the case unsupported and when fired bulge on one side. They are sized backwards to get rid of the bulge before being ran through a regular sizing die. You often end up with a case with an uneven neck. Plays hell on headspace and accuracy.

I feel that this is a dig at glock lover!
Just kidding, he is totally right! That's coming from a Glock loving dirt bag! All Glocks do the same! 9mm, 10mm, 45ACP, 357Sig.

 

[EOD Rob]

I feel that this is a dig at glock lover!
Just kidding, he is totally right! That's coming from a Glock loving dirt bag! All Glocks do the same! 9mm, 10mm, 45ACP, 357Sig.

Not a big issue, just something to watch for. I do not trim pistol unless it does not fit in a case gauge.

 

[Twicepop]

I'll trim brass meant for a revolver load that is getting a roll crimp, but I've never found the need to trim brass that is going to be used in a semi-auto.

 

[rammac]

Seeking some advice from the people who know. Usually I've found that different manuals pretty much agree on case trim length.
I just started to reload the .40 S&W and it seems that the case trim length varies by the different reloading manuals. One manual says 0.845 but another says 0.840. My question is, what's considered too short?

 

[Kracken McGraw]

With .40 it can be worthwhile trim or at least check range brass. You can get stuff with the famous Glock belly or that has had that and been resized.

Glock’s leave the base of the case unsupported and when fired bulge on one side. They are sized backwards to get rid of the bulge before being ran through a regular sizing die. You often end up with a case with an uneven neck. Plays hell on headspace and accuracy.

Thanks for the info, I have been gathering components to start loading 9mm and I have a G19.

 

[skeeljc]

I have never measured or trimmed a pistol case. We shoot 5000 9mm per year. Never had a problem. We buy range pickup brass for one cent a piece and only pick up our brass in practice.

 

[LCazador]

Seeking some advice from the people who know. Usually I've found that different manuals pretty much agree on case trim length.
I just started to reload the .40 S&W and it seems that the case trim length varies by the different reloading manuals. One manual says 0.845 but another says 0.840. My question is, what's considered too short?

The 40 S&W headspaces on the mouth of the cartridge. So a uniform case length will definitely contribute to better shooting. Also with a uniform case length your taper crimp will be more consistent load to load. A case that's too short will go too far forward and may not fire. I trim lot to the shortest case in the lot. Stay within the SAMMI length of -.010 " of .850"