Grains typically refer to the weight of the bullet.

For instance, 9mm bullets come in everything from 95-147gr.. Most 9mm ammo is either 115gr or 124gr bullets. Some people prefer a heavier/slower bullet like a 147gr hollow point, while other prefer a lighter faster bullet.

It goes back to the age old arguement of momentum over energy... 45ACP vs 40S&W, vs 9mm...

In reality, don't get caught up in bullet weight, unless you are reloading for a specific competition, and a specific gun. For defensive shooting, and quality, name-brand hollow-point will usually do.

Some prefer a heavier bullet for shooting through heavier clothing in winter, as a heavier bullet will often penetrate deeper, in testing... In reality??? There aren't enough willing test subjects out there, looking to get shot for the sake of science.

Hope this helps

Jeff Ward

Thanks for the info. So the higher the grain the heavier the round? Could it affect the mechanical function of the weapon?

Originally Posted by mikegray

Thanks for the info. So the higher the grain the heavier the round? Could it affect the mechanical function of the weapon?

It could, and it would. Depends on the recoil spring, and cycling the action. Lighter, more powerful rounds dictate a heavier recoil spring weight generally. The opposite in the heavier, slower moving loads. Again...manufacturers compromise and go for the average when recoil springs are involved. Variables are variables, and you'll experience variables with anything pushed outside the limits, or out of the ordinary. The there is also maintenance and upkeep to think about. Mechanical devices do wear over time.

Your question, "What is more powerful," goes off in the wrong direction.

The "grain" is, in shooting discussions, usually a measure of weight, as Jeff Ward previously stated.
Both bullets and propellant (not "powder," strictly speaking) are measured in grains, which is a subdivision of the ounce. There are 437.5 grains in an ounce. More grains means greater weight (or mass).
In the case of propellant, there is no relationship between the "grains" of the weight of the charge in the cartridge case and the number of "grains" (actually more properly called "granules," or "pieces") of propellant that makes up the charge. Do not confuse the two!
"Powerful" is too nebulous a term. Some people think that "power" means the momentum, or inertia, transferred from a moving bullet to the intended target; but others think that "power" means only the product of multiplying the mass of the bullet by its speed, regardless of whether or not that product is transferred to a target.
In the former case, a heavy, slow-moving bullet may transfer all of its momentum to the target in which it stops; while, in the latter case, a lighter, faster-moving bullet, carrying more momentum with it, transfers much less of its momentum to the target through which it passes completely. So, in these two examples, which one is more "powerful"?
Further, a "more powerful" cartridge loading may cause the inexperienced shooter the pain of heavy recoil, which eventually will cause that shooter to flinch, and thereby to miss his target completely. How "powerful" is that result?
A cartridge loading that you can consistently control will deliver much more "powerful" results than will a Magnum or "+P" load that you cannot comfortably control, shot after shot.
Buy many different loadings, heavier and lighter bullets, more and less velocity, and test them all in your own hands. The loadings you can most easily control will turn out to be the most "powerful" for you.
(That said, my experience leads me to observe that the normal-velocity loads firing the heaviest bullets are usually the most controllable.)

Thanks, I have been trying to figure this stuff out for a while now. I really appreciate the info.

Originally Posted by mikegray

Could the grain affect the performance of the weapon?

In addition to the good information you have already gotten, it might be useful for you to know, at some point, that the weight of the bullet usually affects the point of impact (POI). Typically, a heavier bullet will impact higher on your target, due to it taking slightly longer for it to clear the muzzle, thereby allowing the recoil to raise the muzzle slightly more.

This can be useful to know if you have a handgun with fixed sights that shoots too high or too low. I have had 9 mm guns that shot 4-5" low at 10 yards, with 115 grain ammo, and shot to point of aim (POA) with 147 grain.

When your handgun skills improve to the point that this makes a difference, you should try a variety of ammo to find what each individual gun likes the best. (Some of 'em like everything.)

cool, thanks