[tverho]

Hello, a simple question to the adventurous ones:

Is it technically possible to resize 357sig cases into .40s&w? Has anyone done this? How long is the resulting necked up case? Need of trimming?

Thx!

t tommi

[WatchmanUSA]

tverho, on Nov 18 2009, 02:07 PM, said:

Hello, a simple question to the adventurous ones:

Is it technically possible to resize 357sig cases into .40s&w? Has anyone done this? How long is the resulting necked up case? Need of trimming?

Thx!

t tommi

I'm not sure how one could re-size a .357 Sig case to .40 S&W. If you cut the .357 Sig case down to the proper length for .40 S&W the shoulder diameter is .004 in. larger. You could probably size that down but the problem is the base is .004 larger, too.

.40 S&W - Shoulder diameter .423 in (10.7 mm) Case length 21.6 mm (0.850 in)

.357 Sig - Shoulder diameter 10.77 mm (0.424 in) Case length 21.97 mm (0.865 in)

[mrg]

No, but I'm sure we could trade some .40 for .357 sig.

[Singlestack]

I've done it. Just one round to see what would happen. If you accidental stuck a .357sig case in your press you would never know it. Comes out looking just like a .40.

[WatchmanUSA]

Singlestack, on Nov 18 2009, 09:13 PM, said:

I've done it. Just one round to see what would happen. If you accidental stuck a .357sig case in your press you would never know it. Comes out looking just like a .40.

I didn't think the press would be the problem. A press is designed to resize the brass case. The resizing die won't resize the base. The potential problem is the feeding of the round in mags, barrels and extraction. If the gun is a Glock with a stock barrel there is only a slight risk of a problem but other guns can be more finicky.

[A63111]

I tried to size 1 and the shoulder area still had the creases. Never tried to a load a bullet, but looks as though it could be possible. I would not trust it due to the deformity of the brass.

[Singlestack]

Mine came out smooth. Passed the case gage.

I was scared to shoot it but it would have worked.

[Sean Gaines]

Singlestack, on Nov 19 2009, 07:08 AM, said:

Mine came out smooth. Passed the case gage.

I was scared to shoot it but it would have worked.

Hey guys check this out!

[Singlestack]

Sean Gaines, on Nov 19 2009, 10:08 AM, said:

Singlestack, on Nov 19 2009, 07:08 AM, said:

Mine came out smooth. Passed the case gage.

I was scared to shoot it but it would have worked.

Hey guys check this out!

I am not advocating you do this. I do believe the converted .357sig brass is too short and will cause the round to be head spaced on the extractor instead of the case mouth.

[ben b.]

Singlestack, on Nov 19 2009, 11:49 AM, said:

... brass is too short and will cause the round to be head spaced on the extractor instead of the case mouth.

I think this happens all the time.