Reforming 40 S &W brass to 357 sig brass
- Thread starter Texas Destroyer
- Start date
From a 10 second Google search...
"The issues are that the two cartridges work at different pressure levels, with the 357 Sig operating at higher pressure than the .40. The 357 Sig case has a thicker web, and is thicker at the junction of the wall and web of the case. The 357 Sig is also longer.
There are people who neck down .40 brass and use it, but it's not recommended for the reasons I've listed above. The 357 Sig case was engineered from the ground up for that caliber.
If you choose to do this, then you would have to keep your pressures low, and there will be a problem with the even shorter neck of the necked down .40 case. The 357 Sig neck is short enough as it is to cause some people problems with keeping the bullets from being set back during cycling of the action, and using even shorter necks would exacerbate that problem.
These days there is plenty of proper 357 Sig brass available, so my suggestion would be to just buy the proper brass, if you decide to do the conversion. I have two pistols in 357 Sig, and I've loaded about 15,000 rounds of it. This is one of those rounds that you don't want to cut corners on."
Hope this helps.
Personally I have seen .357 Sig brass sell for about $30-40 per 1000 of used range brass. At that rate I would just buy it, inspect it and develop a load that works in your gun. Plus converting brass sucks, I did about 500 for my 9mm mak a few years back and its painful to loose the cases after all that work, I can't imagine how the 300 BLK people feel.
"The issues are that the two cartridges work at different pressure levels, with the 357 Sig operating at higher pressure than the .40. The 357 Sig case has a thicker web, and is thicker at the junction of the wall and web of the case. The 357 Sig is also longer.
There are people who neck down .40 brass and use it, but it's not recommended for the reasons I've listed above. The 357 Sig case was engineered from the ground up for that caliber.
If you choose to do this, then you would have to keep your pressures low, and there will be a problem with the even shorter neck of the necked down .40 case. The 357 Sig neck is short enough as it is to cause some people problems with keeping the bullets from being set back during cycling of the action, and using even shorter necks would exacerbate that problem.
These days there is plenty of proper 357 Sig brass available, so my suggestion would be to just buy the proper brass, if you decide to do the conversion. I have two pistols in 357 Sig, and I've loaded about 15,000 rounds of it. This is one of those rounds that you don't want to cut corners on."
Hope this helps.
Personally I have seen .357 Sig brass sell for about $30-40 per 1000 of used range brass. At that rate I would just buy it, inspect it and develop a load that works in your gun. Plus converting brass sucks, I did about 500 for my 9mm mak a few years back and its painful to loose the cases after all that work, I can't imagine how the 300 BLK people feel.
thanks i have also thought of using 10mm brass and if i could find 357 sig brass i would buy it because of reasons you stated all very true! if you know of any 357 sig available give a shout
Prices are crazy right now, pre-crazyness last year I was seeing .357 Sig once fired for $40/k all the time.
What I found quickly
http://www.diamondkbrass.com/Handgun-Brass-DKB
What I found quickly
http://www.diamondkbrass.com/Handgun-Brass-DKB
I've bought from these guys before, good folks and quick turn around. http://store.brassmanbrass.com/servlet/-strse-Pistol-Brass-(25-Auto--dsh--38-Special)/Categories
They even have .357 sig in stock ready for you to buy
They even have .357 sig in stock ready for you to buy
+1 on Brassmanbrass. The .357 SIG brass and .40 S&W brass I got from them looked and worked great. Good prices, too, when I bought mine.
Wow!! I just checked their current prices and they've really gone up in what they are asking and selling it in 100 count lots vs. the 1,000 count lot I bought.
Wow!! I just checked their current prices and they've really gone up in what they are asking and selling it in 100 count lots vs. the 1,000 count lot I bought.
I have resized and used a few 40 for the 357 Sig just to see if it would work. Never had any problems, but never loaded it hot either. I had a G32 once upon a time and got rid of it. I have a bunch of regular 357Sig brass if interested. I'll never use it.
When it was first brought out they knew that brass would be hard to find so the cassing was desighned headspace off the shoulder if it can not use the mouth. So you could use 40 or 357 brass. I have access to free 40 brass and I shoot it a couple times and then let it fly. Sizing it is easy just run it in a die just like regular sig brass. Now that the sig is more available I would just shoot standard sig brass.
Just stumbled on this tonight and it jogged my memory.
If you are still looking for once fired
http://www.cheyennebrass.com/once_fired.asp
If you are still looking for once fired
http://www.cheyennebrass.com/once_fired.asp
100% doable!! That is how I make every single piece of my .357 sig brass. I run it all through the 40 cal sizing and depriming die first.... Then run it through the 357 sig sizer die. I use CARBIDE dies! I have not once had a problem and have shot a ton out of my glock. 100% go for it hands down. I have around 1000 pieces of 357 sig sized up right now! Works like a charm.
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