.40 S&W case length question

Gypsysteel · March 24, 2009, 10:37 PM

I've got about 800 rounds of .40 brass that I've prepped & sized, but even after sizing they are only coming out to .837 long. Everything I've found says the minimum is .84, so is all this brass no good?

bullspotter · March 24, 2009, 11:06 PM

I would thinhk they will be fine, mine ar right at .841 .842 area afret sizing, bout .835-.836 before. Im also showing the outer dia of .418-.419 after sizeing but before flairing. Yoer die might not be as tight as mine, are you new to loading the 40? What is the outter dia of your brass after sizing?

bpkmary1 · March 28, 2011, 07:56 PM

Did you reload all 800 rounds? How did they work out. I too have found all of my once fired 40's to be in the .841 to .844 range. Lyman 49 indicates a trim too length of .845. Not only the fired rounds but the unfired factory rounds measure under .845.

Shoney · March 28, 2011, 08:19 PM

Gypsysteel

WELCOME TO TFL!

You do not need to trim straight walled semi-auto pistol brass. Wheel gun cases need to be the same length (OAL).

My experience with straight walled semi-auto brass shows that brass gets shorter with each loading. The cartridge is supposed to headspace on the front lip of the case on the front of the chamber. However, in reality, as the case gets shorter, the extractor holds the cartridge against the slide face where the firing pin can do its job.

Worst case scenario with short brass is that it will likely fall into the chamber and not be caught by the extractor, in which case it will not fire. I have 40SW cases that have been loaded a lot more than 10 times and 45 cases that are somewhere well over 25 loadings. There have been no malfunctions. I put a very light bell on my cases, compared to a lot of other loader, and I think that this reduces shortening. No scientific proof of that though.

bpkmary1 · March 28, 2011, 11:16 PM

Thanx for the reply.. I was kinda thinkin' that was true.

serf 'rett · March 29, 2011, 11:24 AM

...where did the brass come from?

Last week I measured a sampling of some of my 40S&W brass for weight and length. Measured 20 pieces each of Remington, Winchester, Blazer and Federal. The average length for all four brands was 0.843” with the Federal having the widest spread of 0.839” minimum and 0.846” maximum and Blazer the lowest at 0.841” to 0.845”.

Where did you get the short brass? Was it all in the same length range as if someone trimmed it down?

March 24, 2009, 10:37 PM	#1
Gypsysteel Junior Member Join Date: March 22, 2009 Posts: 8	.40 S&W case length question I've got about 800 rounds of .40 brass that I've prepped & sized, but even after sizing they are only coming out to .837 long. Everything I've found says the minimum is .84, so is all this brass no good?

March 28, 2011, 07:56 PM	#3
bpkmary1 Junior Member Join Date: March 28, 2011 Location: CA Posts: 2	Results? Did you reload all 800 rounds? How did they work out. I too have found all of my once fired 40's to be in the .841 to .844 range. Lyman 49 indicates a trim too length of .845. Not only the fired rounds but the unfired factory rounds measure under .845.

March 28, 2011, 08:19 PM	#4
Shoney Senior Member Join Date: February 21, 2002 Location: Transplanted from Montana Posts: 2,311	Gypsysteel WELCOME TO TFL! You do not need to trim straight walled semi-auto pistol brass. Wheel gun cases need to be the same length (OAL). My experience with straight walled semi-auto brass shows that brass gets shorter with each loading. The cartridge is supposed to headspace on the front lip of the case on the front of the chamber. However, in reality, as the case gets shorter, the extractor holds the cartridge against the slide face where the firing pin can do its job. Worst case scenario with short brass is that it will likely fall into the chamber and not be caught by the extractor, in which case it will not fire. I have 40SW cases that have been loaded a lot more than 10 times and 45 cases that are somewhere well over 25 loadings. There have been no malfunctions. I put a very light bell on my cases, compared to a lot of other loader, and I think that this reduces shortening. No scientific proof of that though. __________________ I pledge allegiance to the Flag - - -, and to the Republic for which it stands….Our Forefathers were brilliant for giving us a Republic, not a democracy! Do you know the difference??? and WHY?http://www.wallbuilders.com/LIBissue...les.asp?id=111

March 28, 2011, 11:16 PM	#5
bpkmary1 Junior Member Join Date: March 28, 2011 Location: CA Posts: 2	Great info Thanx for the reply.. I was kinda thinkin' that was true.

March 29, 2011, 11:24 AM	#6
serf 'rett Senior Member Join Date: June 25, 2009 Location: Stuttgart, AR Posts: 1,569	Just Wondering... ...where did the brass come from? Last week I measured a sampling of some of my 40S&W brass for weight and length. Measured 20 pieces each of Remington, Winchester, Blazer and Federal. The average length for all four brands was 0.843” with the Federal having the widest spread of 0.839” minimum and 0.846” maximum and Blazer the lowest at 0.841” to 0.845”. Where did you get the short brass? Was it all in the same length range as if someone trimmed it down? __________________ A lack of planning on your part does not necessarily constitute an emergency on my part.

March 24, 2009, 11:06 PM	#2
bullspotter Senior Member Join Date: November 2, 2008 Location: Montana Posts: 308	I would thinhk they will be fine, mine ar right at .841 .842 area afret sizing, bout .835-.836 before. Im also showing the outer dia of .418-.419 after sizeing but before flairing. Yoer die might not be as tight as mine, are you new to loading the 40? What is the outter dia of your brass after sizing?