What Size Primer Should You Use for 9mm Ammo?

Choosing the correct primer size for your 9mm ammunition is important for the reliability and performance of your firearm.

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In order to ensure reliable ignition, you must use the correct size primer for the 9mm cartridge. The most common primer sizes for this caliber are small pistol, large pistol, and magnum. Small pistol primers are typically used for lighter target loads, while large pistol and magnum primers are designed for self-defense and hunting ammunition.

What is the Standard Size Primer for 9mm Ammo?

The standard size primer for 9mm ammo is small pistol primer. It is generally accepted that small pistol primers are the best choice for 9mm ammunition. There are several reasons for this. Small pistol primers provide more consistent ignition than large pistol primers. They also provide more consistent performance in automatic weapons. Finally, small pistol primers are less likely to cause misfires in handguns than large pistol primers.

What are the Different Sizes of Primers Available for 9mm Ammo?

The most common size primer for 9mm ammo is the Small Pistol primer. These primers are typically used for lighter loads in handgun calibers such as the 9mm, .38 Special, and .357 Magnum. There are also Large Pistol primers available which are designed for use with heavier loads in handgun calibers like the .44 Magnum and .45 ACP.

What is the Best Size Primer to Use for 9mm Ammo?

There are a few things to consider when deciding what the best size primer is to use for 9mm ammo. The powder charge, bullet weight, and type of gun being used all play a role in which primer size will work best.

Generally speaking, a small pistol primer should be used for lighter bullet weights and powder charges, while a large pistol primer should be used for heavier bullet weights and powder charges. For example, a 115 grain 9mm bullet with a light powder charge would benefit from using a small pistol primer, while a 147 grain 9mm bullet with a heavy powder charge would need a large pistol primer to function properly.

The type of gun being used is also important to consider. Some guns are more sensitive to subtle differences in primers than others. For example, Glock pistols are known for being very picky about which primer size is used. If you’re using a Glock 9mm, it’s best to stick with small pistol primers regardless of the bullet weight or powder charge.

In general, small pistol primers are the way to go for most 9mm ammo applications. Only deviate from using small pistol primers if you’re having reliability issues with your gun or if you’re using exceptionally heavy bullets with very heavy powder charges.


In conclusion, the best primer size for 9mm Luger ammunition is small pistol primers. These primers measure 0.175” in diameter and have a cup depth of 0.135”. They will provide good ignition with all powder types and bullet weights in this caliber.