What Do Different Types Of Ammo Do?

What Do Different Types Of Ammo Do?
What Do Different Types Of Ammo Do?

There’s more to a bullet than just a ball of lead and smokeless powder.  In this article, we’re going to go over a bunch of different pistol calibers and then discuss some interesting ammunition options available in them.  There are a lot of different proprietary ammunition types (Hydro Shok, etc.) and while they are indisputably awesome – we’re going to stick the major variants.

Micro Ammunition Classes

There is obviously a lot more smaller ammunition classes but these following examples are definitely common for micro and sub-compact pistols for concealed carriers.

  • .22 LR

Small, lightweight, and extremely affordable – this is often the first ammunition a shooter will ever use.  Recoil is negligible.  This allows the shooter to acclimate to the fundamentals of firearm safety.  Is it still lethal?  Yes.  In fact, .22 LR is a preferred ammunition style for those on long range expeditions who may need to either defend themselves from animals or eat them.  So don’t let it’s small size fool you – it’s capable.

  • .25 auto

This one isn’t nearly as common as it used to be.  The .25 auto round was thought to be the perfect middle man between the .32 auto used in some European police pistols and the .22 round used for recreation.  Recoil is, again, minimal and it affords more rounds into a limited space than a .380 auto.

  • .32 auto

James Bond’s classic Post WWII Walther PPK was chambered in .32 ACP.  Perfect for British spies, old European police pistols, and concealed carriers – pistols chambered in .32 auto tend to fit easily in the palm of smaller hands.

  • .380 ACP

There has been quite some debate as to whether the .380 auto has the penetration power necessary to compete with a 9x19mm round.  It was engineered specifically to fulfill that purpose for micro and sub compact sized pistols.  The big difference between it and a 9x19mm round is 2mm in length.  So, .380 ACP could really be called 9x17mm.

Compact and Full-size Pistol Ammunition Classes
Compact and Full-size Pistol Ammunition Classes

Compact and Full-size Pistol Ammunition Classes

This is not nearly all of the ammunition types that go into pistols.  We’re just covering a few common ones.  Sig Sauer and Glock both make variants that use .357 auto – which is far different than .357 Magnum rounds used in larger revolvers – but are just one example of an uncommon round that we’re not discussing in this article.

  • 9mm (9×19 Parabellum)

9mm is a very common class of ammunition.  It’s used as the primary pistol ammunition for NATO and US militaries.  While the military may be upgrading to .40 S&W and there are special forces operators that prefer .45 ACP and others, 9mm is the most common pistol ammunition.

The most common variety will be the standard Full Metal Jacket (FMJ) – which we’ll get into further on in the article.  With the 9mm bullet, recoil is extremely manageable and magazine capacity is generally increased from similarly sized larger caliber pistols.

  • .40 S&W

This bullet was designed to take all the best parts of the 10 mm Auto round and reduce recoil to a manageable level for the average FBI agent.  The result?  Devastating on soft tissue – as seen in this video of a .40 S&W JHP bullet penetrating ballistics gelatin.

  • 10 mm Auto

The Glock 20 is a perfect example of a modern firearm that uses the 10mm Auto round.  It’s rated to produce slightly more power than a .357 Magnum and less than a .45 ACP.  Though it won the shootout competition for the FBI’s field tests, it ultimately was not selected because of its recoil.  It’s a great round for those with bigger hands and the ability to move with the recoil.

  • .45 ACP

Yes, there is also .45 GAP and a number of other variants.  For the purposes of simplicity, we’re just discussing .45 ACP.  It was a favorite ammunition in the design of the original Colt M1911.  Since then, it’s gained a well earned reputation for low muzzle velocity but devastating impact.  It’s certainly a larger round, causing some to veer away from it due to recoil.

Snub-nose And Full-size Revolver Ammunition Classes
Snub-nose And Full-size Revolver Ammunition Classes

Snub-nose And Full-size Revolver Ammunition Classes

There are revolvers that will accept a wide array of ammunition – some even auto and ACP rounds.  However, the three dominant ammunition types in the revolver market are:

  • .38 Special

The .38 special (it also comes in auto, but we’re not discussing that), was a common round used in revolvers starting around WWI all the way until present.  It doesn’t have too much recoil but still keeps all the best parts of using a revolver: pinpoint accuracy.  In many .38 spc revolvers, the cylinders accept either .38 special or .357 Magnum – making it a very flexible ammunition for a revolver to be chambered in.

  • .357 Magnum

More expensive and definitely more punch, the .357 Magnum boasts an uncanny reputation for a powerful, stand-alone round capable of doing lethal damage to its targets.  The favored round for modern single action revolvers, it’s slightly more expensive than .38 spc and certainly more manageable than .44 S&W.

Ammunition Modifiers
Ammunition Modifiers

Ammunition Modifiers

In addition to the size of the caliber, there are other modifiers used in ammunition to get a desired effect.  A common trade-off is penetration versus spread.  The ideal bullet will both penetrate a target and create massive upset on soft tissue.

  • Overpressurized – +P (+P+)

Overpressurized usually means faster muzzle velocity and greater penetration power.  It takes of a toll on your firearm.

  • Full Metal Jacket – FMJ

The bullet is encased in a thin coating of metal alloy.  This reduces air friction across the point of the bullet, allowing it move faster and penetrate farther.

  • Soft Point – SP

This is a metal alloy coated bullet similar to an FMJ – but they leave the lead tip exposed.  This gives it greater expansion when it strikes soft tissue.

  • Hollow Point – HP

The center of a bullet is hollowed out – creating a mushroom effect upon impact.

  • Center Pin – CP

Just like a hollow point, a center pin is a hollowed out bullet with a post in the middle to control its expansion.  This creates a very large wound channel.

  • Jacketed Hollow Point – JHP

Exactly like a hollow point but with a metal alloy coating to hopefully provide a bit more penetration and foul up your firearm less.

  • Semi-Wadcutter – SWC

It’s a bullet with a flat front surface and a sharp shoulder.  This creates a big wide hole through soft tissue versus sliding through the target.  Decreased muzzle velocity but a crystal clear wound channel.

These are sometimes combined in a specific manufacturer’s make of a style of ammunition.

Ex. Overpressurized Jacketed Hollow Point (JHP+P)

In conclusion, while there are literally hundreds of different types of ammunition for pistols and revolvers, it’s important to be able to identify the caliber with the modifier.  If you can walk into a gun store and know that a case of .40 S&W JHP+P 165 grain Fiocchi is different than 124 grain bulk ammo, this article did it’s job.

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Luke McCoy is the founder of USA Carry. In 2007, he launched USA Carry to provide concealed carry information and a community for those with concealed carry permits and firearm enthusiasts.
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B Penn

Great, but I might have left out the last para since weights were not covered. So what is the difference between 165 gr JHP + P + P and 124 gr bulk case of “what” modifier?
I enjoy your articles aways good info. Thanks.





I find .270 an almost perfect round for any occacian bar none. Next ‘could’ be .338 if I were called to duty as a snipe.


Don’t ‘mean’ to be an ass on purpose….. after-all I am just a dumb mason.
Read, study, & overstand the book of Job.
Every fuc*king act including the 1968 Gun Act must include an exclusion without any harm what so ever evoking such clause. Get your head outa your ass boy.
Book of Job. Read it. Even Satan had to obey.

Dave Elliott

You have something mixed up…the 38 spl cannot chamber 357 magnum cartridges. If you were able to do that, you would blow your gun up, and likely get seriosly injured.
Check out my youtube videos…tagged 357 Ring Of Fire. It is a conversion to have 357 magnum performance with 158 grain bullets in a semi auto, and the magazine capacity of a 9mm.
Dave Elliott

Melissa Robi

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.357 Magnum should not be able to be loaded into a .38 …..a .38 can be loaded into a .357. Something seems to be mixed up a little on that issue.

Tina Sharma

nice article.. Thanks for sharing!