Home Forums Hunting & Shooting Handguns Does size matter? Excellent info here...

The US Army knew this all the way back to the Thompson LaGarde studdies at the turn of the 20th century. All the way back then they had determined that temporary cavity generally doesn't come into play until a projectile is moving about 2,000fps, and even then its kinda hit or miss...like everything else, it depends on where you were hit. If its only muscle tissue, the stretch cavity won't matter much. If it's less elastic material such as intestines, blood vessel branches, etc...then it can be a very big factor. What does it all mean? Well, you still have to place your bullets well, even at 2,000+ FPS.

I agree with you here. The FBI was not a pioneer in the study of terminal ballistics, but built on the work of the ballistics pioneers such as Fackler and his IWBA associates and systematized it in a manner that could allow broad applicability.

Credit is due where it's due. We all owe a huge debt of gratitude to the FBI's ongoing work in the BRF.




I confess I wasn't aware of Mr. Hall's contribution to this work. Thanks for the information.

What I've always wondered is those that say "a 9mm allows you to be more accurate on follow up shots due to recoil recovery" - or some variation of that.

Ok - sure. Great. But what's the degradation in accuracy between the two in any given shooter and more importantly is it large enough you endanger your chances of surviving the encounter? I may open up my group but what are the odds it opens enough to miss center mass? Assuming the first one went there to begin with.

9mm means 6/6 center mass
45 means 6/6 center mass - tho there's more space between them - does that really matter? Does one need benchrest accuracy and repeatability to be effective in an armed confrontation? Obvious answer is no and that's hyperbole. I agree but while everyone's saying "there's a difference!" - I'm wondering if the difference actually matters....

And I don't know how you'd be able to really measure that.

In my personal experience of watching many shooters shoot both the .40 and 9 in identical pistols—Yes, it would be enough to matter in a gunfight.

I see there’s a few of tnoutdoors9’s videos posted in this thread. A few years ago I watched and collected the data from all his vids. I’ll post his data below. I must say up until 12-15 yrs ago I would only carry 45 acp. I have owned and handloaded for all the calibers listed except the .357Sig. I’ve been a handgun hunter since the late 70’s and love the big bores. When I averaged the data of the current factory defense loads I was surprised.

Ballistic gel with 4 layers of denim Avg. of all loads

Velocity / Penetration / Expansion

9mm- 18 loads/ 115-147gr. 1109fps. 14.21”. .625”

.357 Sig- 5 loads/ 125-147gr. 1345fps. 15.14”. .562”

.40 S&W- 10 loads/ 155-180gr. 1086fps. 14.50”. .665”

10mm- 4 loads/ 135-200gr. 1225fps. 15.40”. .684”

.45acp- 13 loads/ 185-230gr. 930fps. 13.84”. .675”

As you can see the ammo factories are producing defense rounds in all calibers to the FBI standards. It’s hard not to carry a round that offers more capacity and still pretty much does the same thing as a larger caliber. At least from the data tnoutdoors9 collected.

Averaging the data waters down the numbers of a particular load that out performs the others. And then there are always the "real world" results that do not always conform to the "numbers".

Interesting thread.

In a full-size handgun that fits well, I'm fine with the .40cal, as the extra handgun mass seems to tame things down to where it feels rather "shootable" and recoil isn't much of a factor. Yes, a 9mm is even easier to shoot, but not that much.

In a compact/micro handgun, the .40cal is too much of a handful in my experience. In that role, I'll settle for a 9mm with good ammo. With neither handgun would I expect a solid torso hit or two to put a grown man on the ground with regularity, but they will likely not have much fight in them and the shooter can likely exit the situation. Dispatching deer and hogs with defense pistol loads tells me that handguns kind of suck for providing decisive incapacitations unless you hit CNS.


Another interesting line of thought is the nature of the perpetrator in a civilian vs. LEO shooting. There are a lot of actual shooting videos out there these days and I don't recall many of the "charging bullet-receptacle" scenarios taking place with private citizens. It seems like most of those bad guys hit the road as soon as any bullets were hitting their flesh, regardless of caliber or bullet construction. It was the LEO shootings that saw occurrences of the guys that soaked up so many hits before stopping their attack. Different pools of participants, I suppose.

Same here... I had a Kahr K-40 at one time... Even though that particular model was all steel, the recoil was just too snappy.. Sold it shortly after..

I know, from experience, big heavy bullets have a visual increase of effectiveness over lighter, smaller calibers on big game animals. When a large caliber, heavy handgun bullet hits bone and penetrates deep or clear through a animal they have a tendency to want to lay down. I can’t imagine a human being much different.