40S&W to 357SIG

[lunchbox]

Hey guys,
So recently I have been doing a lot of brass reforming, taking 30-06 and reforming it to 7.7JAP or 8mm Mauser. So doing this got me thinking, could you do the same with 40S&W to make 357Sig? I don't own 357 Sig dies so I can’t try it. Has anyone ever tried it? The principle sound like it should work Right?
I’m heading to a friend’s house later today and I know he has some 357 sig dies…

 

[woodstock]

Yes Ive made 357 sig cases from 40 brass. be sure to check oal and mouth, shoulder dimensions. RN and FMJ cant be used in 357sig, only HP and possibly flat nose hard cast.

There is a lot more sig brass out there now.

 

[Smiley]

If I recall, .40 S&W has a max pressure of 35kpsi, where as .357 Sig has a max of 40kpsi, so you may have to tone the loads down even if you get the brass to the right dimensions. Some say the .40 brass when re formed isn't quite long enough and for a round that has such a short neck, you may want to watch that closely. It may be possible, but I would just buy once fired .357 Sig brass...

 

[ShineyM3]

I've been tinkering with the idea of reloading but have never done it before and am unsure what's the economy of scale to reloading .40 s&w vs. buying factory? In other words, is it really worth it to do it for .40 s&w?

 

[Jeddak]

Absolutely worth it. I can load match grade 155 and 135 grain HP for less than you can buy FMJ. Key us to reuse the brass and buy bullets in 250 packs.

 

[mojoween]

If I recall, .40 S&W has a max pressure of 35kpsi, where as .357 Sig has a max of 40kpsi, so you may have to tone the loads down even if you get the brass to the right dimensions. Some say the .40 brass when re formed isn't quite long enough and for a round that has such a short neck, you may want to watch that closely. It may be possible, but I would just buy once fired .357 Sig brass...

^^^^This^^^^
Neck tension can be even a greater concern when doing this.

 

[Springfield 1911]

^^^^This^^^^
Neck tension can be even a greater concern when doing this.

Neck tension can get you in trouble very quickly on an already high pressure round with bullet setback. Anytime you work brass or any metal it becomes weaker. Just buy the once fired brass. 357 SIG is more of a pain than it is worth to me. I will just keep my 40 S&W.

 

[Springfield 1911]

I've been tinkering with the idea of reloading but have never done it before and am unsure what's the economy of scale to reloading .40 s&w vs. buying factory? In other words, is it really worth it to do it for .40 s&w?

Loading for the 40 S&W can be rewarding, on the other hand the case is small compared to the bullet and pressure can go up quickly if not seated properly. It is very much worth it though.

 

[Henri311]

I've reloaded and shot 124 gr RN with no problems(so far). Should I pull the bullets and just use flat point or HP bullets? Save the RNs for the 9mm, y'all got me concerned. I just went to the bench, the 124 RNs and the 124 HPs are the same length.

 

[Smiley]

Most FMJ .357 sig I see is FP. I guess the main thing with a RN would be to watch and make sure you are not seating past the ogive and getting a weak crimp or loose neck. I have been interested in loading for the ,357 sig because the components have been rather easy to find during the drought. Accurate #9 is supposedly a fine powder for the round and Longshot looks to be a great load as the volume will provide even greater support to a possibly weak neck. Both of those powders have been pretty easy to find in stock and once fired brass hasn't been hard to find either. I have a GSSF coupon for this year that is just waiting to get used, maybe a 32 is in my future...