Following Tactworld's post about foot-lbs and kinetic energy, I've been trying to decide about what weight bullets to use in my Glocks. So here's my question:

Can anyone tell the difference between shooting 115gr and 147gr bullets? I'm trying to figure if one bullet weight is better than another for competition.

I feel much less recoil from 147 grain than 115 grain.

If you look at the attached chart showing loads for 9mm, maybe it will illustrate why 147 gr is generally softer shooting. When you use a heavier bullet, there is less available room in the case for powder. I initially thought a heavier bullet would also have a heavier charge, but as you can see from the chart, that's not true.

9mm Luger Reloading Data - 9x19 Handloads Information

The exception lies in the 124 grain loads, there you find heavier charges and heavier bullets. Not all 124 grain loads have "heavy" charges, but being that the 124 grain was the "parabellum", or "for war" round, it makes sense that there are plenty of stout loads for that bullet for a variety of reasons.

147 gr bullets are popular in SD scenarios because of the inertia the heavier projectile carries. This is a very simplified attempt at an explanation. But hopefully it will help you begin to look into a very broad subject.

You might also ask your friends/competitors at your matches what ammunition they prefer...

Originally Posted by firewire

Great thread! I've learned a lot! I thought target practice with a 115 would be better, but as EdF702 pointed out that only leaves more room for gun powder!

I find that good standard pressure (not +p) FMJ, like American Eagle, gives me the best accuracy up to 25 yards. The 124 grain shoots the best point of aim to point of impact, virtually spot on from 10 yards to 25 yards. With 115 grain all my 9mm Glocks shoot about 3 inches low and 147 grain shoots about 3 inches above point of aim at the same distances.

It's an interesting exercise to try that for yourself. Get some of each ammo, use a rest, and do some testing. The whole "bullets travel in an arc" seemed like BS until I actually tested the point of aim / impact with different weight bullets.