EXECUTIVE SUMMARY: In identical full size M&P guns, both are more similar than I would have thought.
Went to the range with two M&P full size, one in 9mm and one in .40. I'm used to the nine as it's my EDC gun. But I wanted to see how it compared to the .40.
.40 ammo was:
165 grain Winchester white box FMJ
180 grain hardcast handloads, max load in Accurate Arms reloading guide
9mm ammo was:
115 grain Winchester range fodder
115 grain FMJ handloads, loaded to max +P load in Accurate Arms reloading guide
This is not a quantitative test, just my impressions:
I fired not super rapid fire, but flash sight firing, about a round every second.
I expected .40 to be a whole different category of recoil. But it's really not all that much different. With a firm two hand hold you get a some more muzzle flip. Flip is much more noticeable shooting one-handed. I think if you timed ten-shot strings you'd get ten off a bit quicker out of the 9mm, but not a great deal of difference. If I get a chance to do this test I will.
Firing at the rate I was shooting, accuracy at seven yards was equal. I was putting them in a fist-sized hole in the paper, with occasional outliers. Either one is combat-accurate at ordinary defense distances.
The 9 and the 40 are more alike than they are different, at least in full-size M&P. Certainly neither is in the territory of my XDM 10mm with full power loads. That one is a bigger handful. The M&P is known as a soft-shooting gun and you might have a different impression in some other pistol. I'd bet that there's a bigger difference, say, in 9mm Shield vs. .40 Shield.
I wanted to do a three-way test with the M&P45, but none was available.
In a full-size plastic pistol, either 9 or 40 should be fine for self-protection. I'd still give the edge to the 9mm. Save for possible barrier penetration, the 40 won't do a thing that the nine won't do on a bad guy, and you still have the advantage of more rounds, cheaper ammo, and less recoil.
Went to the range with two M&P full size, one in 9mm and one in .40. I'm used to the nine as it's my EDC gun. But I wanted to see how it compared to the .40.
.40 ammo was:
165 grain Winchester white box FMJ
180 grain hardcast handloads, max load in Accurate Arms reloading guide
9mm ammo was:
115 grain Winchester range fodder
115 grain FMJ handloads, loaded to max +P load in Accurate Arms reloading guide
This is not a quantitative test, just my impressions:
I fired not super rapid fire, but flash sight firing, about a round every second.
I expected .40 to be a whole different category of recoil. But it's really not all that much different. With a firm two hand hold you get a some more muzzle flip. Flip is much more noticeable shooting one-handed. I think if you timed ten-shot strings you'd get ten off a bit quicker out of the 9mm, but not a great deal of difference. If I get a chance to do this test I will.
Firing at the rate I was shooting, accuracy at seven yards was equal. I was putting them in a fist-sized hole in the paper, with occasional outliers. Either one is combat-accurate at ordinary defense distances.
The 9 and the 40 are more alike than they are different, at least in full-size M&P. Certainly neither is in the territory of my XDM 10mm with full power loads. That one is a bigger handful. The M&P is known as a soft-shooting gun and you might have a different impression in some other pistol. I'd bet that there's a bigger difference, say, in 9mm Shield vs. .40 Shield.
I wanted to do a three-way test with the M&P45, but none was available.
In a full-size plastic pistol, either 9 or 40 should be fine for self-protection. I'd still give the edge to the 9mm. Save for possible barrier penetration, the 40 won't do a thing that the nine won't do on a bad guy, and you still have the advantage of more rounds, cheaper ammo, and less recoil.
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