When comparing well designed duty handgun ammunition, there are minimal differences in penetration depths and temporary cavity effects, as noted below in the gel shots by Doug Carr:
As you increase bullet size and mass from 9 mm/357 Sig, to .40 S&W, to .45 ACP, more tissue is crushed, resulting in a larger permanent cavity. In addition, the larger bullets often offer better performance through intermediate barriers. For some, the incremental advantages of the larger calibers are offset by weapon platform characteristics. As is quite obvious from the photo above, NONE of the common service pistol calibers generate temporary cavities of sufficient magnitude to cause significant tissue damage. Anyone interested in this topic should read and periodically re-read, “Handgun Wounding Factors and Effectiveness” by Urey Patrick of the FBI FTU, as this remains the single best discussion of the wound ballistic requirements of handguns used for self-defense -- it is available at: http://www.firearmstactical.com/hwfe.htm .
Keeping in mind that handguns generally offer poor incapacitation potential, bullets with effective terminal performance are available in all of the most commonly used duty pistol calibers—pick the one that you shoot most accurately, that is most reliable in the type of pistol you choose, and best suits you likely engagement scenarios.
The following loads all demonstrate outstanding terminal performance and can be considered acceptable for duty/self-defense use:
Barnes XPB 105 & 115 gr JHP (copper bullet)
Federal Tactical 124 gr JHP (LE9T1)
Speer Gold Dot 124 gr +P JHP
Winchester Ranger-T 124 gr +P JHP (RA9124TP)
Winchester Partition Gold 124 gr JHP (RA91P)
Winchester Ranger-T 127 gr +P+ JHP (RA9TA)
Federal Tactical 135 gr +P JHP (LE9T5)
Federal HST 147 gr JHP (P9HST2)
Remington Golden Saber 147 gr JHP (GS9MMC)
Speer Gold Dot 147 gr JHP
Winchester Ranger-T 147 gr JHP (RA9T)
Winchester 147 gr bonded JHP (RA9B/Q4364)
Barnes XPB 140 & 155 gr JHP (copper bullet)
Speer Gold Dot 155 gr JHP
Federal Tactical 165 gr JHP (LE40T3)
Winchester Ranger-T 165 gr JHP (RA40TA)
Winchester Partition Gold 165 gr JHP (RA401P)
Federal HST 180 gr JHP (P40HST1)
Federal Tactical 180 gr JHP (LE40T1)
Remington Golden Saber 180 gr JHP (GS40SWB)
Speer Gold Dot 180 gr JHP
Winchester Ranger-T 180 gr JHP (RA40T)
Winchester 180 gr bonded JHP (Q4355 or S40SWPDB1)
Barnes XPB 160 & 185 gr JHP (copper bullet)
Federal HST 230 gr JHP (P45HST2)
Federal HST 230 gr +P JHP (P45HST1)
Federal Tactical 230 gr JHP (LE45T1)
Speer Gold Dot 230 gr JHP
Speer Gold Dot 230 gr +P JHP
Winchester Ranger-T 230 gr JHP (RA45T)
Winchester Ranger-T 230 gr +P JHP (RA45TP)
-- Obviously, clone loads using the same bullet at the same velocity work equally well (ie. Black Hills ammo using Gold Dot bullets, Corbon loads using Barnes XPB bullets, etc…)
-- Bullet designs like the Silver Tip, Hydra-Shok, and Black Talon were state of the art 15 or 20 years ago. These older bullets tend to plug up and act like FMJ projectiles when shot through heavy clothing; they also often have significant degradation in terminal performance after first passing through intermediate barriers. Modern ammunition which has been designed for robust expansion against clothing and intermediate barriers is significantly superior to the older designs. The bullets in the Federal Classic and Hydrashok line are outperformed by other ATK products such as the Federal Tactical and HST, as well as the Speer Gold Dot; likewise Winchester Ranger Talons are far superior to the old Black Talons or civilian SXT's.
Basically all the standard service calibers work when using good quality ammunition.
The keys are:
-- Cultivate a warrior mindset
-- Invest in competent, thorough initial training and then maintain skills with regular ongoing practice
-- Acquire a reliable and durable weapon system
-- Purchase a consistent, robust performing duty/self-defense load in sufficient quantities (at least 1000 rounds) then STOP worrying about the nuances of handgun ammunition terminal performance.
Since 1985, at various times I have been issued, qualified with, or authorized to carry the Beretta 92F & M9, Sig P228 & P226, S&W 3913 & 5906, Glock 17/19, S&W 4013 & 4006, Sig P220, S&W 4513 & 4566, various 1911’s, as well as several S&W revolvers including J, K, L , and N-frames. I also have a fair degree of experience with Browning Hi-Powers, Glock 22/23 & 21, various HK pistols, as well as the recent S&W M&P pistols. I have been certified as an armorer on several of these systems. All of these handguns had both good and bad characteristics. I have been lucky to have gotten to travel around the country and world quite a bit and gotten to see what other units and agencies are using and assess how their weapon systems are functioning. There are many pistols which will give adequate service for routine law enforcement or military duty use. The number of pistols which are reliable, durable, and ergonomic enough for very demanding law enforcement tactical and harsh military special operations use is much smaller.
Unless your department picks your caliber for you, pick the platform you shoot best, then decide on caliber from there. Basically all the standard service calibers work when using good quality ammunition; the platform picked tends to dictate the caliber. Currently the best duty pistols going right out of the box are probably the 9 mm Gen 3 Glocks, S&W M&P 40/45's, as well as the HK P30 and HK45.
For CCW and most urban LE duty, there are a lot of advantages in carrying a 9mm--easy to shoot one handed, relatively inexpensive to practice with, lots of bullets. When I injured my strong hand a few years ago and lost its use for several months, I found out how much more effective I was using a G19 weak handed compared to a 1911...
While I am not a big fan of the .357 Sig, if I was issued one and had lots of free ammunition available, I would have no issues about carrying one on a daily basis.
If I was in a department that issued .40 or was doing a lot of LE work around vehicles, I'd be strongly tempted to carry a M&P40. Lots of 180 gr JHP's that do well against intermediate barriers is a nice thing. In addition, I really like having a manual safety on a pistol that is used for uniformed LE use; I have twice seen officers' lives potentially saved when another person gained control of an officer's pistol, but the engaged manual safety prevented the weapon from firing--I don't like to think about the outcome if the pistols involved had been a Glock, Sig, XD, revolver, etc... The M&P40 w/ambi safety and possibly a Performance Center or Apex sear will be the service pistol I'll pick if I ever go back to patrol duties again.
The nice aspects of .45 ACP is that it makes large holes, can be very accurate, and offers good penetration of some intermediate barriers. Unfortunately, magazine capacity is less than ideal, .45 ACP is more expensive to practice with, and in general is harder to shoot well compared with 9 mm. .45 ACP makes the most sense in states with idiotic 10 rd magazine restrictions, in departments that give you lots of free .45 ACP ammo, or in situations where modern expanding ammunition is restricted due to asinine, illogical regulations.
As I've said before:
If you want a Glock, get it in 9 mm...
The HK45 and HK P30 are good reliable service pistols, but beware of HK customer service and parts availability.
These days, skip new Sigs, although the older German made Sig 9 mm’s are superb...
Unless you are issued one and have no other choice, forget Beretta.
XD's are a no go for serious use--the inability to retract the slide without engaging the grip safety makes one-hand injured operation very difficult with the XD--this is a deal breaker for me. In addition, in some government tests, XD's (particularly the .40's) have broken a lot of parts compared to other pistols being tested...I'll take a 9 mm Glock or M&P any day of the week over an XD.
The M&P may just be the best LE service pistol produced to date. I was involved in a M&P40 trial at a large agency where four M&P40's fired 7000 rounds each in 1 week without any significant problems. Up to this point, we have not seen any major problems yet with M&P's (primarily .40 & .45's).
A properly customized 5" steel-frame single-stack 1911 in .45 ACP is a superb, unparalleled choice for the dedicated user willing to spend a significant amount of money to get it properly initially set-up and considerable time to maintain it. Keep in mind with 1911 pistols that calibers other than .45 ACP and barrels shorter than 5" induce increasingly greater problems. I personally will not use any 1911 with a Schwartz firing pin safety (like on the Kimber II pistols) as I have seen high numbers of them fail; the Colt Series 80 firing pin safety is the only one I might trust for urban LE use, but they have also been known to fail in harsh environments (particularly surf zone and high dust) so I generally prefer a standard USG style 1911 pistol w/o firing pin safety. However, I personally would not choose to carry most stock or even semi-custom 1911's on duty without making sure they were set-up properly with reliable function, durable parts, and ergonomic execution. I firmly believe that if you want a 1911 for serious use, the minimum level of quality for a duty/carry weapon is the SA Pro model (either PC9111 or PC9111LR if you want a light rail); if you’re not willing to invest that much into the weapon system, don't get a 1911... I write this after being around quite a few 1911's over the past two decades of military and LE duty, including GI, commercial Colt, SA (Milspec, Loaded, MC Oper, Professional models), Wilson, Kimber, Nighthawk, Les Baer, and Para Ord, as well as custom pistols by folks like Bill Laughridge, Wayne Novak/Joe Bonar, Ed Brown, John Jardine, Hilton Yam, Larry Vickers, and Chuck Rogers. I'd strongly recommend anyone contemplating a 1911 for serious use read all of the material on 1911's here: http://www.10-8performance.com/Articles.html. For folks who want a .45 ACP pistol, but don't want to invest the funds and effort into getting a good 1911, they would be better served with the S&W M&P45 or HK45
In fact, these days, if I already didn’t have several 1911’s that were as reliable as my 9 mm Glocks, along with extensive accessories for 1911’s, I would just use an S&W M&P instead.
Whatever you choose, make sure you fire at least 500 and preferably 1000 failure free shots through your pistol prior to carrying it. If your pistol cannot fire at least 1000 consecutive shots without a malfunction, something is wrong and it is not suitable for duty/self-defense use.
Here is a link to his post. http://www.m4carbine.net/showthread.php?t=19887