Why does bullet weight matter in a handgun?

[kip]

Why do people obsess over 155-180 grain for .40 S&W and 175-230 for .45 ACP? What difference does it make? Wouldnt the heavier projectile make it penetrate and all better?

 

[noah.c.hardy]

There are a whole host of physics principles that come into play in considering ammo weight, however, heavier does not necessarily mean better. Consider the penetration of some light rounds compared to heavier.

 

[Fkimble]

With handguns, it's a tradeoff. Lighter bullets can be pushed faster for better expansion. Heavier bullets are slower but penetrate better but may not expand at all. For a soft target, expansion is often reqarded as better than penetration. For tuff targets, think bear, hogs, cars, penetration is required to reach the vitals. For paper targets, medium weight are usually more accuracy friendly in midrange loads.

 

[flash60601]

Weight and speed of projectile, along with barrel length have a world of bearing on issues between POA and POI.

There are so many combinations, but for discussion, let us speak in generalities here.

A lighter bullet travels faster, and so will travel the length of the barrel much more quickly than a heavier bullet. Recoil, with the barrel rising, is seen as a movement over a finite amount of time. Weight of the gun has some bearing here, but the principle is the same. Lighter bullets will have less percieved recoil, too. So in the (less) time the lighter bullet exits the barrel, the barrel will rise (less) in recoil. So the POI of a lighter bullet will be LOWER than a heavier bullet with the same POA, all other things being - - GENERALLY - - equal.​

Is that vague enough?

Flash

 

[thndrchiken]

Because on recoil operated loading designs bullet weight can play a factor in how much recoil is generated, therefor affecting the reliable and consistent operation of the gun.

 

[scattershot]

I suspect that it doesn't matter as much as folks think it does. Both heavy and light will work if you put them in the right place. That said, I like heavy bullets, but paper targets don't know or care how much a bullet weighs.