M&P in .357 Sig

[colt_saa]

Makes sense since the .357sig is a .40s&w case necked down to accept a 9mm bullet.

Actually, this is a common misconception. The 40S&W is not the parent case of the 357SIG cartridge.

357SIG is a unique design.

Resizing a 40S&W to 357SIG will yield a case that is approximately .10" too short. It will function but you lose quite a bit of neck tension on the projectiles.



357SIG and 40S&W do share case head dimensions and overall length

 

[Walt Sherrill]

Resizing a 40S&W to 357SIG will yield a case that is approximately .10" too short. It will function but you lose quite a bit of neck tension on the projectiles.

Sounds as though you'd have to start with a 10mm casing and do the scrunching and trimming from there.

 

[Deadeye Dick]

Actually, this is a common misconception. The 40S&W is not the parent case of the 357SIG cartridge.

357SIG is a unique design.

Resizing a 40S&W to 357SIG will yield a case that is approximately .10" too short. It will function but you lose quite a bit of neck tension on the projectiles.



357SIG and 40S&W do share case head dimensions and overall length

I stand corrected.

Now that I think about it I believe it was based off of the 10mm Auto which the FBI initially tried but decided was too hot for their female and smaller framed male agents to handle effectively so they and S&W shortened the .10mm Auto case, reducing the powder capacity. If my recollection is correct that is how the .40s&w (Short & Week) was born.

 

[ShelbyV8]

The FBI watered down the load for the 10mm. S&W found that they could get the FBI velocity out of a 9mm length case making it easier to adapt to 9mm sized weapons. S&W developed the round but Ruger got the first weapon to market. The FBI didn't adopt the 357sig but several other government agencies did Secret Service,. Air Marshalls and some lesser known.

 

[lkabug]

I have no complaints about mine. Accurately is great, recoil isn't bad at all