Reloading the .357SIG

PoFF

PoFF

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Now that i got myself a nice P226 in 40S&W, I'm thinking of getting a 357SIG barrel just for the heck of it. I've got a few questions about reloading for this caliber.

1. Case forming : I've read at many places that it is totally not recommended to resize .40S&W cases to .357SIG cases, but I know that many people do it anyway without problems. My two main concerns would be that a .40 necked to 357 would be a tad short, and since I've heard it headspaces on the mouth and not on the soulder, it might prove to be a problem. Plus, .40 brass is rated to 35K CUP while 357 is rated at 40K CUP.

2. Powder choice : Im my Hodgdon manual, only 3 powders are listed (Longshot, HS-6 and Universal). I scratch Universal because of poor performance in this caliber, and HS-6 because it's too smoky & dirty, leaving only Longshot. Is there a recipe using Titegroup?

3. Dies and Sizing : Since it is a bottlenecked caliber, but there are Carbide Dies available for it, but it's also a pistol caliber, so it has thinner walls so it's easier to resize, would I need to lubricate casings before sizing?
 
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You'll need lube. Fotunately Dillon spray lube works great.

Gunnar is the de-facto guru on this topic, but bottleneck cases, even pistol cases, should be sized to headspace in your gun on the shoulder.
 
PoFF said:
1. Case forming : I've read at many places that it is totally not recommended to resize .40S&W cases to .357SIG cases, but I know that many people do it anyway without problems.
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Lots of people I know drive drunk too. I've seen some of the 'home made' .357 sig brass and it is definitely short. And 'short' in all the wrong places. IMHO save your time and buy some 357s brass. One of the 'biggest problems' (so many say) with the 357 sig round is that there is already too little surface area to prevent push back of a bullet on chambering. With the resized .40's I would say this would be twice or three times as likely... .40 and .357 are high pressure cases, and there is a fine line between high pressure and too-high pressure, with some powders a little over half a grain is 10000 psi increase at the top end. Setback on a hot load is just as dangerous. Setback happens with resized .40s. Period. Why risk it for a couple bucks? Sounds like this is just a secondary round for you in this gun anyways so I say don't skimp on the brass. My $0.02
 
Once fired brass is only a little more for 357 sig than .40s&w... when you find it.

I have a .40/357sig p226 also. One problem is the bullets, you need flat point bullets, or they end up being to long, or you have to shove them in to far, and you loose case tension.

I havn't loaded verry many, but the few I have didn't require case lube in regluar lee steel dies.
 
357 sig from 40 no problem

The solution to this problem is simple. I know the 357 sig head spaces on the mouth but it doesn't have to. All you have to do is simply size the cartridge so that it head spaces properly on the neck. The limitation to this is the ammo is customized for one gun and shouldn't be used in any others. Sure you can say that 357 sig is not much more than 40. But since 40 is popular and thus free I would argue 357 sig is a lot more.
 
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