What’s The Right AR Rifle Caliber For You?

One of the most exciting things about the AR is its ability to chamber different rounds with work as simple as changing the Upper Receiver assembly and the top half of the gun, thereby giving you a weapon with a whole new set of capabilities. This flexibility means that you can build a gun that is capable of clambering a huge variety of rounds – in fact, there are so many different calibers available that it becomes bewildering, and without a bit of background knowledge, you risk picking something that is, perhaps, not appropriate to your needs.

So, what are the most prominent rounds and what is best for how you plan on using your gun?

1.) The .223 Remington.

Standard fare for the AR-15 and great for general shooting, pest control, and even some potentially competitive shooting. With the right gun set-up, this could be decent at longer ranges. You need to be a little careful since while this round is interchangeable with the 5.56 NATO, the NATO round should not be fired in rifles marked up as being .223 Remington. On the other hand, feel free to shoot .223 Remington ammunition in a 5.56 NATO rifle. This one-way sharing of round-type makes these everyday workhorses cheap and economical to use.

2.) The .300 Blackout.

When it was first devised, this round was available as either sub-sonic or super-sonic forms, but in those two guises, produced very mixed performance, with the sub-sonic version being the most stable. However, it is notable for producing very little recoil in its supersonic form and in therefore a great cartridge for instructing young or new shooters, while giving a good degree of accuracy. With a good selection of loads to choose from, as long as you are sticking to either sub-sonic or supersonic, you’ll get some good and consistent results, just no so much if you mix them up through the same gun.

3.) The .22 Long Rifle.

Bringing recoil way down, the chambered .22 Long Rifle (LR) round is both exceptional in limited performance and great for instructing on gun safety with a young or new shooter. There is a great array of conversion kits available that allow you to modify your stock AR-15 to fire the LR round, and with these smaller calibers being cheap to buy, you can have fun all day and not even worry the bank. Furthermore, the .22 LR round is more than capable of dealing with everything up to medium-sized varmints with ease.

4.) The .25-45 Sharps.

This round was designed to allow the AR to be used as a big game round in every one of the States. Based on the standard .223 cartridge, but necked up to accept a .257 bullet, it has a good ability to take out sizable game at medium ranges, while offering low recoil. The main problem with the .25-45 Sharps is that there are currently no major bullet manufacturers stocking it and you may have to go some distance – or at least a good internet search – to be able to procure some of these. With low recoil for such a handy round, it might be best to invest in a hand-loader instead if you want to keep a good supply of these in the cupboard.

5.) The .30 Remington AR.

From its development in 2008, the .30 Remington is undoubtedly the best round for snagging big game, if you can manage to find any! Using the .30 Remington requires the use of a special bolt assembly, but since many AR owners love to tinker with their weapons, that doesn’t represent too much of an issue. The problem with the round is that Remington didn’t market it very well, and put out performance data that suggested that the .30 was low on performance. The market reacted by with apathy and sales nosedived, which is a shame as the .30 Remington represents one of the finest performing rounds that you could push up an AR-15 barrel. The load will push a 150 grain bullet up to 2,600 fps and that is actually the kind of performance that you need to take down a large pray from a distance. If you can find them, these are an excellent round!

6.) The .350 Legend.

Available in a series of weights, starting at 145 grains, and ranging up to 265 grains, the Legend was developed specifically for hunting deer, and produces more power at the muzzle than the .223 Remington, .30-30 Winchester and .300 Blackout, but with as much as 20% lower recoil. That makes this an impressive round that is ideal for the serious hunter, but is equally good at many other tasks such as close protection and long-range target shooting too.

7.) The 6.5 Grendel.

This round has actually been marketed as a jack of all trades round and it is ideal for a great number of shooting styles. The round is heavier – and thus slower – than the 5.56×45 NATO bullet but offers a flatter trajectory and is therefore more effective over a greater distance. Recommended for long range shooting, competition shooting, and potentially some hunting. While there are better options for deer hunting, the 6.5 Grendel would be acceptable in the eyes of most users.

8.) The 6.8 Remington.

Allied to the 6.5 Grendel, this was designed specifically to be an improved round on the standard 5.56 NATO bullet, and is actually the bullet from the .270 Winchester cartridge. Lager and heavier still than the 6.5 Grendel, the 6.8 Remington is an effective round with many fans, but a proportion of serious hunters actually prefer the 300 Blackout, though that round doesn’t have the range of the 6.8 round.

9.) The .458 SOCOM.

A big daddy of a bullet, this round was designed following demands from the Special Operations community who were looking for a bullet that delivered more punch than the standard AR-15 rounds. They got that and this is a round that is highly effective at shorter functions such as close combat or home defense, with the trade off that it is fairly useless at any shooting done over a distance. Anything that you hit with a .458 SOCOM will go down, as long as it is not too far away.

10.) The .224 Valkyrie.

One of the newest rounds on the market and one that is making big waves. While it may be insufficient for big game hunting in some States, the 75-grain hollow-point load has a muzzle velocity of 3,000 fps, making it a great all-round product. Based on the 6.8 SPC case with a .224 round fitted, there has been a fair amount of reworking to make it work. With sales rising fast, the .224 Valkyrie is likely to overtake the best selling .22 Nosler as the best all-round option for the AR-15.

This is just a small selection of the rounds available for the AR-15, and one of the wonders of owning such a gun is the modifications that you can carry out, and after reading this guide you should be able to find a caliber that will fit your purposes perfectly.