The AR rifle platform is a favorite for many American shooters because it’s versatile and available in a number of calibers and cartridges useful for target shooting, home defense and hunting.
You can cover the spectrum with an AR, but that begs the question: What’s the best AR caliber or cartridge for your situation?
In this article, we list the best AR calibers & cartridges available in 2025 and why they work well whether you’re taking an AR to the range, hunting, or defending your home.
If you can’t wait, the 22 Long Rifle (22 LR) tops this list. If you want to see the full AR caliber list, keep scrolling.
My Top 6 AR-15 Caliber Picks
Here are our favorite AR-15 caliber choices:
- .22 Cal
- 6.8 SPC - Best AR-15 Caliber for Home Defense
- 6.5 Grendel - Best AR-15 Caliber for Long Range
- .30 Cal
- .355 Cal / 9mm
- .45 Cal
Let’s examine each AR caliber and cartridge in depth to help you choose the best one for your shooting needs.
Testing Procedure
I considered many factors while choosing the best AR calibers and cartridges for this list, including (but not limited to):
- What was the cartridge designed for?
- Ballistic performance
- Price
- Functionality
Understanding why the cartridge was created and how it fits into the AR platform is the best way to choose the one that suits your preferences.
How the cartridge performs ballistically is another key factor you must consider. A long-range cartridge is great for target shooting but will be impractical for home defense.
All of us are on some sort of budget. Just as many of us want ammo that will stay within that budget’s confines – without forfeiting reliability.
Lastly, if the cartridge doesn’t function well in the AR platform, it shouldn’t be on the following list. I rounded up cartridges that have proven to function reliably in the AR platform.
My Top 11 AR-15 Cartridge Picks
| Cartridge | Best For |
|---|---|
| 22 LR | Best Overall |
| 6.8 SPC | Best For Home Defense |
| 6.5 Grendel | Best For Long-Range |
| 6.5 Creedmoor | Most Accurate |
| 300 AAC Blackout | Best AR Pistol/SBR Cartridge |
| 6mm ARC | Best For Hunting |
| 22 Nosler | Best For Varmints |
| 308 Winchester | Best For Big Game |
| 450 Bushmaster | Best For Whitetail |
| 458 SOCOM | Best For Hogs |
| 50 Beowulf | Best Big Bore Security |
22 LR - Best All Around AR Cartridge
Pros & Cons
| Pros | Cons |
|---|---|
| Low recoil | Only good for hunting small game and target shooting |
| Inexpensive | Limited effective range |
| Cheap & easy conversion | Rimfire primers are inherently less reliable than centerfire ones |
Why I Chose It
If you’re like me, the first shot you ever fired was with a .22 LR rifle. As the most popular round on the planet, the .22 LR is unquestionably the best AR round thanks to its negligible recoil, extremely low cost, and high availability.
The greatest benefit of the .22 LR in an AR-15 platform is that it allows you to train with your standard 5.56 NATO rifle for a fraction of the cost. Converting an AR-15 to 22 LR only requires a conversion bolt and new magazines, as any AR 5.56 barrel can safely handle 22 LR. It’s much easier than converting an AR to a cartridge of a different caliber, as doing so requires a new barrel.
AR-15 22 LR conversion bolts and magazines are inexpensive, and 22 LR bulk ammo is dirt cheap and fun to fire. You can spend a day firing 500 rounds of 22 LR for approximately one-fifth the cost of the same amount of bulk 5.56.
6.8 SPC - Best AR-15 Cartridge for Home Defense
Pros & Cons
| Pros | Cons |
|---|---|
| Designed for CQB | Fewer options |
| Suitable for medium game hunting within 200 yards | Relatively expensive |
| High striking energy compared to 5.56 NATO |
Why I Chose It
The 6.8 SPC makes an excellent choice for home defense, as it was developed specifically for close-quarters and mid-distance combat and has exceptional short-range terminal ballistics.
Developed in 2004 as a joint operation between Remington Arms, U.S. Special Operations Command (USSOCOM), and the U.S. Army Marksmanship Unit (USAMU), the 6.8mm Remington Special Purpose Cartridge (SPC) was designed to improve the terminal performance of the M4 carbine.
The program aimed to produce a cartridge that mimics the stopping power of the 7.62x39mm. In general, the 6.8 SPC was successful at accomplishing this task. However, due to chamber design issues when Remington first presented their new round, the 6.8 SPC was not adopted by the Armed Forces.
The U.S. military may have passed on the 6.8 SPC, but that doesn’t mean it’s ineffective. On the contrary, the 6.8 SPC is an especially potent short-range cartridge, boasting a 45% increase in muzzle energy compared to a standard 5.56 NATO M855 load.
Its added kinetic energy makes the 6.8 SPC an excellent choice for a home defense carbine. It is also popular for hunting deer and hog within 200 yards.
Continue reading 11 Best AR Calibers & Cartridges in 2025 for Target Shooting, Home Defense & Hunting on Ammo.com
