*There is NO disadvantage in regards to SD distances between a Sight radius on a 3" gun to a 4" barrel gun. ! inch cannot make that much difference at ten to 12 yards.
There's no established hard limit, either legally or practically for SD distances. It is true that handgun encounters are more likely to be close range affairs, but there's nothing that constrains them in terms of some arbitrary number of yards.
Does sight radius make a huge difference? Not really, but it does have some effect--potentially significant. Going from a PM9 to a G19 is a 21% increase in sight radius length which will reduce the effect of aiming errors on the target by about 21%.
So, for example A 0.05" sighting error will put the bullet off by 4.4" from the aiming point at 12 yards with a PM9. The same error with a G19 will result in missing by only 3.6"--about 20% smaller miss distance.
*There even could be an argument that in a physical struggle, a smaller gun would be harder to grab by the perp than a larger pistol.
Good point. It might also be possible to demonstrate that the larger grip makes it easier to retain a full-sized gun. I don't know that I've ever seen any studies like that--the results would certainly be interesting.
* The Kahr has been 100 percent as reliable as any of my larger weapons.
I carry a Kahr too. So far it has been very reliable. But in general, I have found that smaller semi-autos tend to be less reliable, more likely to be grip sensitive, and also more likely to have durability issues. I'm not saying that they are garbage or anything, just pointing out that some issues tend to be more likely with small guns. Ran into an article awhile back about someone who had bought a very small gun in .40S&W. The upshot was that he was never able to get acceptable reliability out of it. The small size and light weight made it so grip sensitive that he could only shoot a magazine or two out of it before it started malfunctioning due to weakening grip. Now that was an extreme example, but it does illustrate a good point.
Another thing to consider about grip sensitivity issues is that a poor grip is more likely in an SD situation. I noticed that in videos of real-world shootings, it was surprisingly common to see malfunctions even in full-sized guns that are normally considered very reliable. I finally realized that it was very common for a person in a high-stress situation to get a poor grip, to shoot one-handed, to shoot from awkward positions, or to shoot with an injury that precluded a strong/firm grip.
It's something to think about. As I said, it hasn't stopped me from carrying a small pistol, but I do realize that there could be ramifications.
* Very little recoil on the Kahr PM9....recoil, flip and control are largely determined by the ability of the shooter.
As I said, I have and shoot small Kahr pistols. The recoil is not punishing, but it is more than in a full-sized pistol. Same with muzzle flip. So much as to create a dangerous liability? Obviously not, or I wouldn't carry one for self-defense. But there's no free lunch when it comes to physics. Lighter guns will recoil more and have more muzzle flip, all else being equal.
FWIW, I can shoot the Kahr as well as the glock 19.
That would be pretty unusual. I think that operating with a timer and under some incentive to shoot as well as absolutely possible, you would see a significant difference between your performance with the two guns. I'm very accurate with my little Kahr, but when it comes to putting accurate rounds down range in a hurry, I do better with a larger gun--I've never run across anyone who shoots better with a small/light gun than with a larger/heavier gun in the same caliber when both speed and accuracy are factored in. The recoil recovery difference isn't something that can be escaped. It can be minimized, and someone with a lot of hand/upper body strength can probably make the difference a lot smaller, but it's not going away.
Ok, one other thing I noticed. The reason for carrying a PM9 is ostensibly capacity restrictions. While I get tjhe point and agree that carrying a smaller gun makes more sense when one can't carry more than 10+1 rounds, I don't think that a 10+1 capacity restriction is valid justification for going to a gun that only holds 6+1 rounds. I'm not saying anyone is under obligation to get right up to the limit, just that a solution that involves carrying a gun with a capacity of more than a third fewer rounds than the limit seems inconsistent with the stated problem. (Yes, I know that there are 7 round mags for the PM9, but the point remains that a 6+1, or 7+1, or 8+1, etc. carry gun is very likely being chosen for some reason other than to address a 10+1 capacity limit.)
Now if you cannot shoot a small gun well, I get it.
Not the issue at all. When I was adjusting the sights on my carry gun, I showed the final target to the range owner and asked him if he thought it was centered up well enough. He asked me about the target and when I told him I shot it at 25 yards, he looked at the gun and said: "With THAT gun?!" I still chuckle when I remember his expression. It's not that it's impossible to shoot small guns well, it's that people perform better with larger guns for a number of reasons.
You put in the time and diligent training, you reap big rewards.
Definitely true.
If a fellow used his micro pistol and ends up at the top of the class, what does it matter if he even could shoot his larger pistol better, but chooses to use the smaller one for CCW? He's still way ahead of the curve.
Sure. A person can get very good with a small gun. I often carry a small gun and there's no way I would do that if I hadn't achieved a satisfactory level of performance.
I think that part of what's going here is that we have some people talking about a
difference in performance levels with small guns vs. full-sized guns and some people talking about an
absolute level of performance with small guns.
Also, I think that some folks are interpreting the comments about comparative performance as if those comments are impugning their performance with small guns.
People can get very good with small guns. But the physics of recoil, and issues like sight radius mean that those same people will shoot better with larger guns. NOT that they necessarily shoot badly with small guns, but that their performance will be better with a larger gun.