9mm_40

[BP1]

if i understand this right the 40 and the 9 are the same gun all but barrell and mags, so how does the 9 withstand 40 pressure, i thought guns were built around the caliber.

 

[rsrocket1]

The M&P was designed around the 40 S&W cartridge, it's not an upscaled 9. The 9mm barrel is simply thicker so it fits essentially the same slide. The 9mm slide is machined with a little less metal taken out in order to accommodate portions of the 9mm barrel. So essentially an M&P9 is in theory stronger than an M&P40.

Both are made to handle the 35,000 psi SAAMI specs for their respective cartridges. 9mm +P is actually 38,500 and is not recommended for everyday use, although it's OK for carry purposes.

 

[Lost Lake]

The slides are the same, recoil springs are the same, the .40 however uses a .40 barrel.

That's how the 9mm can handle .40 loads. It uses a .40 barrel!

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