MP-Pistol Forum banner

9mm and 40 ballistics

3106 Views 13 Replies 9 Participants Last post by  bchandler
First of all, I'm not trying to start an ammo war! I'm trying to decide on my new M&P (I don't have one yet). I'm generally a fan of bigger and heavier, since handgun ammo is so underpowered for self defense anyway. But, when 9mm ammo is $13 a box of 100, and 40 is $20 per 100, well, practicing hurts a lot less. However, my firearm will also be used for concealed carry, so effectiveness is important.

I know, shot placement is important. I do not see myself having time to aim precisely if my life is ever threatened though. I am thinking center of mass here. My question pretty much is: how (objectively) do the best high power loadings of 9mm (+p or +p+) compare to the best 40 caliber? Double tap lists .40 165 grain gold dots at 1140fps from a 3.5" barrel (M&P compact size) for a total of 476 f/p. They have 9mm 124 gr +p at 1295fps from a 4" barrel (so a little less from the compact) for a total of 462 f/p. My question is does the size of the round itself help in defense at all? Or is effectiveness merely a matter of weight and velocity?

Thanks for the help, just trying to make a good decision for myself... hope I don't start any caliber wars :/.
1 - 14 of 14 Posts
The benefits of ramping up velocity are overrated. A drop in velocity however can be problematic, but that's not going to be an issue in a 3.5" .40 or 9mm. There are standard pressure 9mm loads available that will do just fine. You can go +p or +p+, but its just not necessary IMO. I use Winchester Ranger 147gr RA9T in my 9mms. With a .40, you're going to get better barrier penetration and slightly larger permanent wound cavity. I use Winchester Ranger 180gr RA40T in my .40s.

There isn't much difference ballistically between the top 9mm defensive loads and the top .40 defensive loads; or any of the defensive calibers for that matter. You should choose the caliber you have the most confidence in; and the caliber you shoot the best.

Right now I shoot mostly 9mm because of cheaper ammo costs. I feel totally confident that my little 9mm will do the job. If ammo costs were of no concern, I would probably go with .40 because it does have a slight edge ballistically, being it has a slightly larger caliber and bullet weight.
+1 for 9mm

it has been around for 105 years for a reason 8)

plus cheap ammo = more time at the range :wink: If you do the research, you will have a different opinion on 9mm rounds and how it compared to others in the FBI Ballistic Test Protocol. This link shows what they did to conclude their findings. Here are some interesting findings:

If you look at the history behind the FBI spec, you will find the shootout between some FBI agents armed with 9mm semi auto pistols against better armed bank robbery suspects, the end result of that fight led to the development of the 40 S&W cartridge. In the years since that shootout bullet technology has advanced tremendously, but in a contest between 9mm and 40 S&W the 40 is the better choice of caliber.

However, bullet placement is the key to winning any gunfight, a solid hit with a 9 is far preferable to a poorly placed 40 S&W bullet.

You pay your money and make your choices, each person has to determine their own parameters, and that's the only real answer.

Thanks to all for the help.

Morgan Walker- I looked at both of those links, but both only seem to explain methodology behind the tests. Do you happen to have a link to tests of modern JHP loadings so that I might see for myself?
bchandler said:
Thanks to all for the help.

Morgan Walker- I looked at both of those links, but both only seem to explain methodology behind the tests. Do you happen to have a link to tests of modern JHP loadings so that I might see for myself?

I know this is a long read, but Massad Ayoob wrote this himself on ballistics of home defense rounds.

Here is a topic on 9mm vs .380 ACP for self defense, it has what I think you are looking for.

Nice find, thanks for sharing...

You might like to check out . Lots of good info on hipowers (obviously) as well as many other handguns and there's a page with lots of in depth info on the old 9mm vs 45acp debate. I know it's not .40 but the same idea, small/fast vs big/slow.

Check out his site, lots of interesting stuff.
Cruise around Doc's site,

If you shoot .40 well (some people don't) and can eat the price difference, then I'd bump to the .40 caliber. All things equal, the .40 IS the better round, its the details (your split times between shots due to recoil differences, the cost of practice ammo, ect) that make or break it for you.

So, do you shoot .40 well? Are you skipping lunch so you can afford to go to the range once (or twice or three times :twisted:) a week? Are you insecure about your manliness? If you answered yes to the last one you might want to hold out for the .45...or 10mm

..These are all very personal and important questions to consider
See less See more
Well, I can shoot my 23 well but have no 9mm to compare it to. I'm also considering just getting a reloading press with these crazy ammo prices, but then the follow up shot factor plays in too. I wish some range had both to compare :/. I have a range that rents the glock 19 I could compare to my 23, but I don't think that's be apples to apples with the M&P compacts.
1 - 14 of 14 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.