i have heard that barrel length affects the power of a round. for example, in a compact handgun, 3-4" barrel, is a smaller round actually more powerful. would a .40 or .357 sig be better for stopping power than a .45 in a gun with a short barrel.

Sure, a longer barrel will generally yield higher velocities, which will affect bullet performance.

But all rounds are going to be affected by barrel length, not just the larger ones.

Key is matching your ammunition to the expected velocities - no matter what the bore size.

Check with manufacturers to see what ammo the recommend for a particular barrel length.

Most auto cartridges are usually chambered in guns which may have barrels between 3-5" in length, sometimes slightly shorter or longer. If your concern about "power" means your worried about it's effectiveness as a "stopping round " being affected by Barrel length, don't sweat it. Mathematically velocity is increased or decreased as barrel length changes but in a pistol 1" won't make an appreciable difference to anybody on the receiving end of the projectile. Rifle folk are always decreeing the merits of barrel length on performance in the field and these guys have a much larger range of barrel lengths to choose from sometimes as much as 8-10" in some calibers . While this will record on their chronographs it's usually not going to play itself out on some game animal. I don't think there has ever been a deer lost because of a22" bbl being used instead of a 24"-er and the bullet failed to reach the deer.

444fitch

444... is right -- it doesn't make much practical difference. As a rule of thumb, is use 50fps per inch of bbl length change for straightwalled pistol and 100 fps for bottle-necked cases. This formula works pretty well for most purposes.

There is a point of diminshing returns. If the barrel is of sufficent length already to allow full gas expansion lengthing the barrel will actually slow the bullet down due to increased friction. Of course, this point is different for every caliber. For .22 lr this point is about 18". Barrels beyond this length will actually shoot slower.

Sir,

I quite agree with the gentlemen that posted prior. I doubt much difference in pistol bullet performance due to barrel length, as pistol bullets are somewhat flimsy affairs anyway.

The issue with barrel length to me is that longer barrels are easier to more precisely align the sights, and I personnally shoot much straighter with a longer sight radius that a five inch pistol (Kimber, Beretta) offers.

I tend to disregard performance of the bullet, as it strikes and may expand/ penetrate, and tend to be more performance oriented on putting the bullet in the right place to start with. Longer barrels help me out in this tremendously.

Good SHooting.

Steve