I'm not too sensitive to recoil so I never paid much attention, but if you shot 9mm and 40S&W loaded to have similar power factors (minor) in the same brand/type of gun (e.g M&P9 and M&P40), would you be able to tell the difference? If so, what would the main differences be?

I have not had the pleasure yet to see how they compare to one another in similar style guns, but I would suspect the .40 is going to just be a more snappy round compared to the 9mm.

 

I'll be able to tell you the difference for real come next month, I'll have my CZ 75-TS in .40 with minor loads and I'll be able to shoot my new to me CZ 85B Combat in 9mm with minor, very similar guns in weight and sized so unless someone else jumps in with an answer (that will probably take 5 minutes) I'll let you know on the 5th or 6th of December.

 

ETA: Actually you come out to OB don't you, if you do and I am there I know I will have both in December on so if you want to check it out for yourself, you are more than welcome to shoot both of mine, I'll have both minor and major loads for both also being I like to carry a lot of ammo as long as I am not going swimming..

All things being equal I think they would feel the same. But 9 and 40 frequently use different powders which will feel different and if the recoil spring is different that will probably come through also.

 

I'd be interested in a 1-to-1 comparison if someone did it though.

They are going to be diffrent, Tuning the gun to a specific load will reduce recoil.

You can have a .45, for example, with a higher power factor feel like it recoils less than a .40 with a lower power factor. What matters to feel is the time the recoil impulse is imparted to you. This is why .40's tend to feel snapier even though the energy is less. The recoil impulse is very short comared to the longer recoil impulse of the .45. So even if they were dead even in power factor, I think you would "feel" less from the .45. Hope that came out clearly This is purely speculation on my part. I havent tested this theory.

Good points and they make sense. I was considering a 9mm as my next pistol. Since I have an M&P40 and if using minor ammo will make it comparable to a 9mm, then I don't see much reason to get the 9mm.

Power factor is just a number. Recoil will feel different. Two different guns firing same ammo will feel different.

IMHO, minor in a 40 "feels" better than minor in a 9mm.

I shot a knock down steel match using all 40 minor loads and it felt very comparable to a 9mm. I decided that I'll skip getting a 9mm for production USPSA and just use my M&P40 with the minor loads. Now I can use it for production, limited and limited 10 and maybe put the money towards a 1911 open gun in 38 super.

same power factor does not equate to the same feel for the recoil. That isn't to say that you can't Get a minor .40 to feel like a minor loaded 9mm. Load 165gr 40 to about a 130pf, and it will feel a lot like a 124gr 9mm loaded to 135-ish pf, but with less sight movement than the 9mm. It will also put down steel plates better. It'll also cost more to load.

Good points and they make sense. I was considering a 9mm as my next pistol. Since I have an M&P40 and if using minor ammo will make it comparable to a 9mm, then I don't see much reason to get the 9mm.

 

9mm is nice to have being it's cheaper to shoot. I have adjusted my plan, CZ75-TS for USPSA Limited & L/10 (Major) and Knockdown steel (Minor) and us the CZ 85B Combat for Static steel and USPSA Production. Plan subject to change as always.