9mm question: difference between 115gr, 124 gr, & 147gr?

[JDW67]

Why choose one grain over the other? I do notice the larger grains have a slightly slower fps. What advantage or disadvantage between the grains?

Thanks in advance

[Burbur]

First, energy at impact. Much like the arguments between 9mm and 45 ACP, the heavier bullet normally has more energy to transfer to a target, whether that be a body of a steel plate that need to be knocked over.

Recoil. lighter bullet, less felt recoil (at the same velocity)

Feeding. Some guns just like different bullet profiles. Sometimes different profiles come at increased mass. Find one that doesnt jam.

Power factor. In competition shooting, you can meet minimum power factor ratings at lower velocities.

[KahrGuy9]

Energy is based on mass and velocity. So a very, very fast 115 9mm may have more energy than a slower 147 mm. My experience is that recoil is much greater with the faster lighter bullets than the heavier bullets. Alot of guys run the 147 gr just for that reason, you only need to go 850 fps to make the power floor of 125 for USPSA. And any falling steel has to calibrate to a 125 floor. Bullet shape is always a factor for any particular gun model, but most stuff works. The real difference is price point, 115/124's are cheaper than 147's. And because the 9mm standard is 115 grain, some guns will shoot the 147's a couple of inches high at 15 yards.

[mjmagee67]

Power factor is just bullet weight X velocity. As long as that exceeds either 125000 for minor or 165000 for major your good to go. I shoot Production in USPSA when I started I used 115gr bullet but now have moved to 124gr. I did try 147gr bullets but the slide felt sluggish to me. There are quite a few shooters who like 147s but they didn't feel good to me. I even tried a lighter recoil spring, but the gun didn't always lock up. So for me my pet load wings a 124gr bullet out there at 1050 fps. As far as knocking over steel, all steel us supposed to be calibrated using a round with a PF of 115-120 so as long as you make PF you shouldn't have an issue. You should shoot for 5 over on your PF.

As far as felt recoil 124s felt less that 115s at the same PF. 147s did feel the lightest as far as recoil. If you want to shoot USPSA you will have to experiment with loads to find what you like the best.

[JDW67]

Thanks everyone. I'm going to try the 124 gr to see how it effects my shooting.

[ScottyXbones]

Are there any factory loads in 124gr that come in right around the 125 power factor?

[mjmagee67]

Are there any factory loads in 124gr that come in right around the 125 power factor?

I believe most are over 125 around 135 to 140. BUT you don't want to load just to 125, most go 5 over to have some cushion. Not all Chrono's run the same. No one wants to pay $200+ for a big match and not make PF. I have yet been to a local match that Chrono's BUT I want to shoot the same ammo all the time so I have one load. I do know people who load down a little for local and load up for big matches. To each his own, normally it's only .1 to .2gr difference in powder.

You will most likely NOT get the advertised velocity on the box, you will be slower.

[Kokopelli]

A Recoil calculator: http://huntamerica.com/recoil_calculator/ Plug is some numbers and see how much your lead launcher kicks.

[billrd]

A Recoil calculator: http://huntamerica.com/recoil_calculator/ Plug is some numbers and see how much your lead launcher kicks.

Pretty neat. But what about the powder type?

[KahrGuy9]

As far as knocking over steel, all steel us supposed to be calibrated using a round with a PF of 115-120 so as long as you make PF you shouldn't have an issue. You should shoot for 5 over on your PF.
.

True, alot of clubs will have a much lower calibration floor for poppers, but per the rules, it is 125. Steel plates are not subject to caibration.

[rm1911]

others mentioned power factor, which is important in competition. heavier bullets are easier to make factor than lighter ones, by and large. as for just general all around range fodder, I honestly will shoot either 115 or 124 and not really worry. I like 5.7-6 grains of either #5 or power pistol, and both 115's and 124's shoot great. so I'm nt picky and neither are my guns. in fact, I usually shoot xtreme plated bullets, and with neither do I get enough velocity to worry about the plating.

as for a better defensive round, this is a different issue. velocity used to be the game, but now it seems heavier is the ideal. something to do with penetration and weight retention, and other stuff that 1000's of pages of articles have been written about. I think most LE uses 147's, and if you do, practice with what you carry. point of impact will vary and that's the biggest issue.