Anonymous asked in SportsOutdoor RecreationHunting · 1 decade ago

What is the best bullet caliber for a semi-automatic?

Question 1: If you had to choose between 9mm, 357 sig, 40 s&w, and 45 acp, which would you prefer and why?

Question 2: Which gun manufacturer do you prefer?

19 Answers

  • H
    Lv 7
    1 decade ago
    Favorite Answer

    Between the calibers you have listed I'd go with:

    .357 Sig (for superior stopping power)

    9mm (for Universal availability and usefulness)

    .45 acp (for availability & stopping power)

    .40 S&W (because it was made to duplicate the performance of the .45)

    None of the above would be my first choice for a semi-automatic caliber. My first choice is (and has been for the last dozen or so years) the 10mm in a Glock Model 20. This one does it all. It gives you true magnum performance out of a semi-auto pistol. The Glock is high cap, durable, dependable, user friendly, accurate-as-the-shooter and the 10mm caliber is as powerful at a 100 yards as the .45 acp is at the muzzle.

    I listed the .357 Sig first on your list because it too is of magnum performance in a semi-auto. It comes close to duplicating the performance of the .357 Magnum which is still known as the best manstopper yet. Next I listed the 9mm simply because it is more available anywhere in the world you go. With proper defensive ammo it is a good manstopper and practice (ball & FMJ) ammo is cheap enough to make for a lot of practice. Even though the .45 acp comes a close second to the .357 Magnum as a manstopper most .45s don't have the ammo capacity of the 9mms, .357 Sig, or even the big 10mm. Ammo in .45 acp is not quite as Universally available as is the 9mm and the .45 acp performs poorly against barriers such as doors, sheetmetal & car glass (which is why many police agencies like DPS have switched from the .45 acp to the .357 Sig).

    I placed the .40 S&W last because although it has gained so much popularity with policemen it is just the 'short-n-weak-son-of-10. That is, why have a .40 when you can have the 10mm that really does do it all! Back in the Sixties when I begin my law enforcement career many lies were told about the .357 Magnum that today are being repeated about the 10mm. All because some non-handgun persons were afraid of the .357 Magnum. People who fear the 10mm whine and cry about the 10's vicious recoil, etc., etc., etc. and so the .40 S&W was created. In the Sixties because people whined & cried about the .357 Magnum police were force to use the really poorly performing .38 Special with the lead ball 158 grain ammo. Today no one considers the .38 Special (especially with ball ammo) even a marginal defensive handgun. Now the .357 Magnum is recognized as the best manstopper to date. Do you see history repeating itself with the 10mm vs. the .40 S&W? If you still decide that the .40 S&W is really your cup-of-tea then select the best defensive ammo you can find for it. You could do worse than the .40 and after everything is said and done ammo selection is more critical than caliber when selecting a medium to large bore defensive handgun.

    Good luck.


  • Anonymous
    5 years ago


    What is the best bullet caliber for a semi-automatic?

    Question 1: If you had to choose between 9mm, 357 sig, 40 s&w, and 45 acp, which would you prefer and why?

    Question 2: Which gun manufacturer do you prefer?

    Source(s): bullet caliber semi automatic:
  • 1 decade ago

    I always look to the worlds military and the weapons and calibers they use.

    All of these weapon systems are tested well beyond what we can understand in the fact that these were used in fully automatic weapons.They withstood the most grueling of conditions and have stood the test of time. The most common handgun calibers used in the worlds armies are the most popular in civilian weapons as well. The 9mm. and the 45 ACP. They have been a mainstay well before WW 2 and are still # 1.

  • 1 decade ago

    I would feel confident with ALL the calibers mentioned. Although, there are slight advantages and disadvantages to each round they are all proven and meet the FBI’s 12" penetration requirement.

    Manufacturers I prefer are those that back their pistols with longer than usual industry warranties and have good customer support services. However, I don't rely on a pistol's reliability because of a manufacturer reputation. Rather I believe that EVERY pistol rolling off the assembly line is different. The only way to know if you have a reliable pistol is to put lead down range with different defensive loads. Basically, the pistol regardless of the manufacturer most prove its reliability to me....the shooter.

    My daily carry is a semi-auto chambered in 45 ACP. I like the idea of heavier bullets and larger wound channels for a self-defense pistol. As for manufacture the S&W PC department has been always courteous and sent me free recoil and other replacements spring for free! So they deserve this plug!!!!

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  • 1 decade ago

    You didn't state what you're using the gun for; target or self-defense or all around.

    For plain target shooting, I'd go with the 9mm in any SIG pistol.

    For self defense, I use and advise towards the .357 SIG cartridge; great energy and awesome penetration. Handguns are inherently weak compared to rifles and such, regardless of what we think. That makes penetration very important. I've used all of them and carried some of them in the Army. My second choice would be between the .40 and the .45.

    For semi-auto handguns, I prefer Sigs. Especially the P226; finest combat handgun ever made. That being said, there are many that are okay firearms. I avoid S&Ws because, as a gunsmith, I've seen more S&Ws come in with problems than any other handgun by far. Next in that list would be, believe it or not. .45 auto variants of the 1911 variety, usually because someone tried to 'trick them out' and tighten them up. They become very finicky about what they'll feed reliably.

    Get a Sig, if you can afford one; if you can't, get a Ruger. Both of these are dead-on reliable; they just don't seem to break.

    You'll get more opinions about this than what flavor of soda is best. Good luck!

    Source(s): lifelong shooter, hunter, gunsmith
  • 1 decade ago

    They all have advantages and disadvantages.

    9x19 Parabellum is the most widely used 9mm cartridge. It allows users to carry greater capacity compared to larger caliber rounds and also has less recoil than them. This allows quicker and more accurate firing. 9mm's stopping power and penetration is moderate. It has a kinetic energy of 440-480 J and a muzzle velocity(the speed of the bullet when it leaves the muzzle) of 300-360 m/s depending on the bullet weight

    .357 SIG has much higher kinetic energy and muzzle velocity than most hangun cartridges. It is good against body armor for the tremendous penetration it creates compared to all other handgun cartridges. The recoil of .357 SIG is very strong though. If you want to use a 357 caliber round, use .357 Magnum instead because it is known to have slightly better performance than .357 SIG. .357 SIG has a kinetic energy of 700-830 J and muzzle velocity of 380-470 m/s depending on bullet weight.

    .40 S&W is similar to 9mm Parabellum in all ways but has %50 more energy (that pretty much means %50 more power). Plus, its recoil isn't too strong for a large-caliber round. If you wanted to use 9mm, don't. Use this instead since it is one step ahead 9mm. .40 S&W's k. energy is 500-800 J and its m. velocity is 320-420 m/s.

    .45 ACP is a very versatile round that combines excellent accuracy with exceptional stopping power and moderate recoil. It is roughly equalivent with .40 S&W in many ways. Because it is a subsonic round (its velocity is lower than the speed of sound) it has low penetration and therefore it isn't very good against body armor but still .45 ACP is the most powerful round that can be used with a suppressed handgun/submachine gun. .45 ACP has k. energy of 700-870 J which is very high and m. velocity of 310-420 m/s.

    My choice would be .45 ACP because it is great in almost all ways and it is used in M1911 pistol which is one of my favourite handguns. If you want penetration though, .357 Magnum is the answer.

    And for the gun manufacturer question; Heckler&Koch is a great manufacturer. I just love the sturdiness of HK manufactured guns such as G3, MP5, G36.

    Note: I am no professional hunter or something, I just like weapons and I study a lot about them. I've never even fired a real gun before.

    Source(s): lots of books about guns
  • 1 decade ago

    A1: 45ACP. Good accuracy and stopping power. If you must fire one without any hearing protection in a hurry, it will not hurt your ears as badly as other calibers. If used on small games, a 45ACP FMJ will damage very little edible meat.

    A2: Caspian - They make great stuffs for 1911's. Precision, reliability and durability. Simply great stuff. A little costly though.

    Glock - Glock 21 is one of the best out of the box semi-auto combat handgun money could buy. It's very rugged and durable. It's very reliable if you did your part. It will not win any bullseye competitions but it's plenty accurate for a combat handgun. It's trigger is not light enough to cause accidental discharges but it also not heavy enough to effect your accuracy; this is how triggers should be for a service/combat handgun. There's no safety switch to mess around with yet it is a very safe handgun. I'd prefer if their empty factory magazines could drop out of the grip freely though.

  • 1 decade ago

    9mm and 40 S&W (Short and Wimpy) are only worth while to carry if you have access to free ammo, or, are a woman and cannot handle the better 45 acp. The 357 Sig - good luck finding ammo in some places.

    45acp is the king of semi-automatics. It has the best stopping power and control.

  • 1 decade ago

    If you are going with a flatgun, it should be a .45 ACP.

    It is not the fasted cartridge, and it might not be the most powerful, but it has been a reliable man-stopper for almost 100 years. And since the .45 ACP is a smokeless imitation of the original .45 Long Colt revolver cartridge, the ballistics have been recognized as superior as man-stoppers since 1873.

    My favorite .45's are revolvers, Colt Single-Action Army revolvers (and the Italian copies), Ruger Blackhawks, Smith & wesson M- 625's, and Smith & Wesson and Colt Model 1917's.

    In flatgun configuration, my favorite .45's are:

    Colt Model 1911(especially Combat Commanders and Officers' ACP models) and Sig P-220's. Everything else is in "also ran" category.


  • 1 decade ago

    1. I prefer the .45ACP because of three things: the 1911 series, making large holes in paper, and accuracy. 9mm would be my second choice because it's more economical and has plenty of different bullet weights for factory ammo.

    2. I prefer Kimber 1911 guns (equal to or greater than the nicer Springfields. For a 9mm I would prefer Beretta or that ever-expensive classic FN-Browning High power.

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