Ammo Taylored To Micro Compacts

[Goffman]

I know I jumped into this discussion far too late and if everyone is tired of it then please just tell me to shut-up. My question, should anyone choose to entertain it, is in regards to the difference in a 147 grain vs. 124 grain. There have been some folks on this thread saying that the 147 grain performs better in the short barrel (3" barrel) that many of our Kahr pistols have. I am confused at that. I had read in the past that the heavier bullet slows down less (as a percentage) than does a lighter bullet, but it seems like the performance stats of a 124 +p are so much higher than a 147 (as far as fps and fpe) that the 147 grain would still have lower performance. In other words, if say the 124 +p looses 10% in a 3" barrel (vs. a 4" barrel) and the 147 grain loses say 5%, but the 124 +p starts out at around 1150 fps and 395 fpe...and the 147 starts out at 1000 fps and 320 fpe (just estimating numbers) wouldn't the 124+p still end up with higher fps and fpe? How could the 147 actually hit harder and expand more?

I am all for using 147 grain. I even bought some from LGAmmo, but I still don't understand how it can actually perform better than 124+p. In a few videos I saw on youtube, it looked like 147 grain tended to penetrate deeper, but didn't expand quite as much on average?

Thanks to anyone willing to answer my (probably) uneducated questions?

You're correct about your assertion here. The problem is in the definition of "performance". Folks tend not to provide a concrete definition of the word "performance" when they make claims that X performs better than Y. For example, is performance referring mainly to velocity, to energy, to momentum, to expansion, etc.?

In short barrels, the 124 has considerably higher velocity than does the 147, and, despite the difference in mass, the excess velocity of the 124 provides a meaningful advantage in energy. This holds true even for the standard pressure 124 versus the 147. The difference in momentum, though, is not great. Hence, the 147 moves at a slower velocity than the 124, tends to expand less, and penetrates slightly more, all else being equal.

It's true that the 147 loses less velocity (see http://www.ballisticsbytheinch.com/) in short barrels than does the 124, but the 147 is starting at such a disadvantage in terms of velocity that the lower "loss" can't make up for the initial disadvantage. That isn't to suggest that the 147 doesn't "perform well", whatever that means. Whether it performs well or not depends on the definition of "performance". Using more concrete terms, though, the velocity of the 147 is notably lower than the 124 even in short barrels.

[DKD]

All of what JOSHH said was true and accurate. The only thing that wasn't mentioned is that one also has to take into account not only the powder charge weight but the burn rate of the powder.
One has to be aware that a critical balance of pwoder charge, vs rate of burn has to be balanced to accommodate the shorter barreled hand guns. Most heavier slugs from a given calibre tend to use a slightly slower burn rate powder...hense a longer dwell time of the bullet in the barrel to utilize the powder charge. many of the better manufactrures have been tring to find a compatable faster burn powder that would be consumed in the shorter barrel carry guns to maximize the muzzle velocity of a given bullet. The faster burn rate powder also tends to have the added advantage of a lower muzzle flash, desirable in low light conditions making follow up shots easier without lose of your night vision.
I personally prefer the 124 grainers in my 9mm pistols, to ensure the better chance of bullet obturation due to the higher muzzle velocity. Please keep in mind the design of the bullet plays a key roll on whether the bullet will expand at a given velocity.
whew...! that was a mouth full.

[joshh]

that quote actually came from Paul Nowak Senior Technical Specialist for Winchester Law Enforcement Ammunition. i like the win defense ammo and i only tried the 147gr and the 124+p & personally thought the 147 shot and performed better. i think in a bad situation either would be better than a blade or bat.