Smith & Wesson MP barrel lockup: can it be cut down?

[Army GI]

I'm fairly new to the S&W M&P. I owned one standard sized one in 9mm but I sold it before I got a chance to fire it. Now I want to get one of those beautiful M&P Shields.

However I want it in .357 Sig. So I was thinking of getting the .40 version, and buying a .357 conversion barrel and just having it cut down to size.

If I cut down that barrel, will it still work in the gun? How does the barrel lock up into the frame? Is there a barely noticeable flare at the end of the muzzle that locks up with the frame like a bushingless system in a 1911? Or can I cut and recrown the barrel and everything will be GTG?

[autoduel]

Yes, there is a slight flare at the end of the barrel.
But I have a full size barrel in my compact and accuracy didn't seem to be affected significantly. It shoots slightly higher than the compact barrel, but comparing the groups, I didn't see much difference. But this was when I had less than 300rnds through the gun. I'm tempted to compare the 2 next friday.

[P5Ret]

I'm not sure it would work, since the Shield frame is significantly thinner than the standard M&P. I would think the frame lock up would need some mods also. Maybe someone who has a standard M&P and a shield can take a pair of calipers to the barrels and let us know if there are any differences in the sizes. It would be interesting to find out one way or the other.

[Army GI]

That would be quite appreciated

[John Browning]

The two do not interchange.