10mm case trimmed to 40 S&W

Gdouthit · January 14, 2013, 01:44 PM

noobie question here

I was at the range the other day and saw a bunch of 10MM cases on the ground. I am wondering if it is O.K. to trim these cases to .845 ish and run them through my 40 S&W?

Thanks!

WIL TERRY · January 14, 2013, 01:56 PM

ONLY IF YOU ARE WILLING TO CHANCE the 40's tabbing the large primer on a 10MM cartridge. GO back and check the history of why S&W went with SP primers in their 40S&W.

david_r · January 14, 2013, 02:23 PM

unless you have the skill to work up a custom load, that probably isn't a good idea. Look inside one and compare it to your 40. Trim one to length and then compare the volume it has versus the volume of an actually 40 S&W shell. Besides, do you really want to monkey with small primer vs. large primer when you can buy once fired for so little money? You could probably sell the 10 mm if you have enough to offset a lot of the cost.

If you have a speer reloading manual, read their section on 357 sig. Same applies to 40 S&W from 10mm.

Now, I have no experience with the 10mm. But it seems to me that if the 10mm has a beefier base and someone did have the skills to create a custom round to chamber in 40 S&W, he might have a round that wouldn't bulge so bad in an unsupported chamber. A rube-goldberg solution to a non-issue? Quite possibly.

greentick · January 14, 2013, 03:41 PM

I wouldn't chance cutting those things down.

I'd be happy to reimburse your postage and recycle those cases properly

Gster · January 14, 2013, 05:38 PM

I'd put them up to swap for what you need. I picked up a bunch of .357 sig. that the game wardens shot at their range. I put them in brass traders on a couple different forums and ended up with some .9mm and .40 s/w.

RickB · January 14, 2013, 06:44 PM

Quote:

You could probably sell the 10 mm if you have enough to offset a lot of the cost.

I can find .40 brass on the ground at the ranges I frequent, and would gladly trade them 2-for-1 for 10mm brass.

m&p45acp10+1 · January 14, 2013, 06:57 PM

Do not trim down 10 mm brass. People that reload 10 mm would be glad to trade for .40 S&W brass. Most likely two for one.

Nathan · January 14, 2013, 07:06 PM

Lots of decent replies...

...but, I have to ask...what is "tabbing" a primer?

In a nut shell, you would need to trim and check volume. One of your issues would likely be the thicker stronger case mouth.

It would be a challenge to get a half decent load. It is also basically a sin to destroy more expensive brass to make cheaper and more plentiful brass.

Shadow7d · January 14, 2013, 07:09 PM

for the time and effort you would need to spend
you could simply SELL the 10mm, buy .40 once fired and walk away with a profit... and be MUCH further ahead time, equipment, and effort (not to mention money wise)

Oh, and the LP in .40 had issues with being struck on the truncated nose of the bullet behind it, usually only a problem in tube guns, but it was an issue, I forget why, in .40

edward5759 · January 14, 2013, 07:17 PM

Gdouthit
I've done it and it did not result in any real advantage.
I had 7.0 gr of unique with a 155 gr bullet.
Pressure went up and the cases started to show a little stress.
I have a barrel in 40 S&W for my universal receiver So I have the ability to measure pressure.

I will be glad to trade brass though

Edward5759

serf 'rett · January 14, 2013, 07:56 PM

Don't do it.

Should be an easy trade to someone looking for 10mm.

Besides, I think I recall something about the webb being a little thicker, which would reduce capacity and result in increased pressure. That would explain the results edward5759 observed.

Gdouthit · January 14, 2013, 10:08 PM

Thanks for the replies! Really wasn't sure with it using a large pistol primer.

orionengnr · January 14, 2013, 10:41 PM

I am another who would be happy to trade .40 brass for 10mm brass...two or more for one.

January 14, 2013, 01:44 PM	#1
Gdouthit Junior Member Join Date: January 11, 2013 Posts: 7	10mm case trimmed to 40 S&W noobie question here I was at the range the other day and saw a bunch of 10MM cases on the ground. I am wondering if it is O.K. to trim these cases to .845 ish and run them through my 40 S&W? Thanks!

January 14, 2013, 05:38 PM	#5
Gster Senior Member Join Date: September 2, 2012 Location: N.central Pa. Posts: 302	I'd put them up to swap for what you need. I picked up a bunch of .357 sig. that the game wardens shot at their range. I put them in brass traders on a couple different forums and ended up with some .9mm and .40 s/w. __________________ Gun control means: Being able to hit what you are shooting at.

January 14, 2013, 06:57 PM	#7
m&p45acp10+1 Senior Member Join Date: May 3, 2009 Location: Central Texas Posts: 3,930	Do not trim down 10 mm brass. People that reload 10 mm would be glad to trade for .40 S&W brass. Most likely two for one. __________________ No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.

January 14, 2013, 07:17 PM	#10
edward5759 Senior Member Join Date: September 15, 2009 Location: Phoenix, AZ. 30 miles from water, two feet from Hell. Posts: 355	Gdouthit I've done it and it did not result in any real advantage. I had 7.0 gr of unique with a 155 gr bullet. Pressure went up and the cases started to show a little stress. I have a barrel in 40 S&W for my universal receiver So I have the ability to measure pressure. I will be glad to trade brass though Edward5759 __________________ Failure is part of success! This year will go down in history. For the first time, a civilized nation has full gun registration. Our streets will be safer, our police more efficient, and the world will follow our lead into the future!" -Adolf Hitler,1935"

January 14, 2013, 07:56 PM	#11
serf 'rett Senior Member Join Date: June 25, 2009 Location: Stuttgart, AR Posts: 1,569	Don't do it. Should be an easy trade to someone looking for 10mm. Besides, I think I recall something about the webb being a little thicker, which would reduce capacity and result in increased pressure. That would explain the results edward5759 observed. __________________ A lack of planning on your part does not necessarily constitute an emergency on my part.

January 14, 2013, 01:56 PM	#2
WIL TERRY Senior Member Join Date: July 6, 2000 Location: BLACK HILLS Posts: 1,322	ONLY IF YOU ARE WILLING TO CHANCE the 40's tabbing the large primer on a 10MM cartridge. GO back and check the history of why S&W went with SP primers in their 40S&W.

January 14, 2013, 02:23 PM	#3
david_r Senior Member Join Date: January 9, 2013 Posts: 131	unless you have the skill to work up a custom load, that probably isn't a good idea. Look inside one and compare it to your 40. Trim one to length and then compare the volume it has versus the volume of an actually 40 S&W shell. Besides, do you really want to monkey with small primer vs. large primer when you can buy once fired for so little money? You could probably sell the 10 mm if you have enough to offset a lot of the cost. If you have a speer reloading manual, read their section on 357 sig. Same applies to 40 S&W from 10mm. Now, I have no experience with the 10mm. But it seems to me that if the 10mm has a beefier base and someone did have the skills to create a custom round to chamber in 40 S&W, he might have a round that wouldn't bulge so bad in an unsupported chamber. A rube-goldberg solution to a non-issue? Quite possibly.

January 14, 2013, 03:41 PM	#4
greentick Senior Member Join Date: January 15, 2011 Location: Deep South Posts: 261	I wouldn't chance cutting those things down. I'd be happy to reimburse your postage and recycle those cases properly

January 14, 2013, 07:06 PM	#8
Nathan Senior Member Join Date: July 1, 2001 Posts: 6,325	Lots of decent replies... ...but, I have to ask...what is "tabbing" a primer? In a nut shell, you would need to trim and check volume. One of your issues would likely be the thicker stronger case mouth. It would be a challenge to get a half decent load. It is also basically a sin to destroy more expensive brass to make cheaper and more plentiful brass.

January 14, 2013, 07:09 PM	#9
Shadow7d Member Join Date: June 12, 2010 Location: Alaska Posts: 42	for the time and effort you would need to spend you could simply SELL the 10mm, buy .40 once fired and walk away with a profit... and be MUCH further ahead time, equipment, and effort (not to mention money wise) Oh, and the LP in .40 had issues with being struck on the truncated nose of the bullet behind it, usually only a problem in tube guns, but it was an issue, I forget why, in .40

January 14, 2013, 10:08 PM	#12
Gdouthit Junior Member Join Date: January 11, 2013 Posts: 7	Thanks for the replies! Really wasn't sure with it using a large pistol primer.

January 14, 2013, 10:41 PM	#13
orionengnr Senior Member Join Date: July 9, 2004 Posts: 5,173	I am another who would be happy to trade .40 brass for 10mm brass...two or more for one.

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