Guides

Best AR Caliber for Hunting, by Game Size

Match the cartridge to the animal and to your state's rules — those two constraints eliminate most of the list before preference ever enters into it.

Start with the legal constraint, not the ballistics

Before comparing cartridges, check two things in your state's regulations: whether there is a minimum caliber or energy requirement for the game you're after, and whether your hunting zone is restricted to straight-wall cartridges.

Straight-wall restrictions exist in a number of midwestern states and are the entire reason cartridges like .350 Legend and .450 Bushmaster were created. If you hunt in one of those zones, that requirement decides your caliber before anything else does.

Regulations change and vary by county and season. Verify with your state wildlife agency — this page is a starting point for research, not a legal reference.

Varmints and predators

For coyote, prairie dog, and similar, you want flat trajectory, light recoil, and a frangible bullet that doesn't damage a pelt more than necessary. 5.56 with light 40–55gr varmint loads is the obvious, cheap answer, and .224 Valkyrie or 6mm ARC extend that same profile substantially further if you're taking longer shots.

Deer and hog

This is where the AR-15 platform's mid-size cartridges earn their place. 6.5 Grendel and 6mm ARC both deliver good bullet weight and downrange energy from a standard AR-15 frame with mild recoil — a real advantage if you're carrying the rifle all day or want fast follow-ups.

7.62x39 works at woods distances with the right expanding load. On the AR-10 side, .308 Win is the proven default and is legal and effective essentially everywhere deer are hunted.

5.56 for deer is legal in some states and not others, and is widely considered marginal. If you do it, it demands a purpose-built controlled-expansion hunting bullet and disciplined shot placement — not ball ammo.

Straight-wall states

.350 Legend is the mild option: light recoil, inexpensive, effective on deer at woods ranges, and easy for newer or recoil-sensitive hunters to shoot well. .450 Bushmaster is the heavy hitter — substantially more energy and knockdown on deer and hog, with recoil to match. .458 SOCOM goes further still and has the unusual advantage of running well suppressed with heavy subsonic loads.

All three run on an AR-15 frame, which keeps the rifle light and familiar.

Elk and larger

Step up to a large-frame AR-10. .308 Win is the practical floor for elk with good bullet selection and disciplined range limits. .338 Federal offers more frontal area and energy on larger animals while still fitting a standard AR-10. 6.5 Creedmoor is popular for its flat trajectory and mild recoil, and works well with premium controlled-expansion bullets at responsible ranges.

Bullet construction matters more than the caliber argument here. A well-built controlled-expansion bullet from a modest cartridge outperforms a poorly chosen bullet from a bigger one.

Our picks

Best AR-15 deer round6.5 GrendelReal downrange energy and mild recoil from a standard AR-15 frame.The proven default.308 Win / 7.62Legal and effective essentially everywhere, with the widest ammo selection.Straight-wall states.350 LegendLight recoil and inexpensive, purpose-built for straight-wall regulations.Big-bore knockdown.450 BushmasterSubstantially more energy on deer and hog where straight-wall rules apply.

Common questions

Can you hunt deer with a 5.56 AR-15?

It's legal in some states and prohibited in others, and it's widely considered marginal for deer. If your state allows it, use a purpose-built controlled-expansion hunting bullet rather than ball ammo, and keep shots close and well-placed. Cartridges like 6.5 Grendel, 6mm ARC, or .350 Legend are better suited to the job on the same platform.

What is a straight-wall cartridge state?

Several states restrict deer hunting in certain zones to straight-walled cartridges rather than bottlenecked rifle cartridges. That rule is why .350 Legend and .450 Bushmaster exist. If you hunt in one of these areas, the restriction determines your caliber — check your state wildlife agency's current regulations.

Is 6.5 Grendel or 6mm ARC better for hunting?

They're close. 6.5 Grendel has a longer track record and a more mature ecosystem of barrels, bolts, and magazines. 6mm ARC shoots flatter with less wind drift and was designed more recently around high-BC bullets. Either is a solid AR-15 deer cartridge; pick based on ammo availability where you live.

Put it into practice — the builder checks compatibility as you go.

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Legal & safety disclaimers (read me)

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Sound Is Ranked, Not Measured

ArmoryBench does not publish decibel levels. A 2026 review of published suppressor data found that most manufacturers release either nothing at all or bare numbers without the test standard, weighting, and microphone position needed to compare one against another — and that most cartridges have no published unsuppressed reference level whatsoever. Rather than present figures assembled from sources like that, we show a relative ranking: how loud one configuration is likely to be next to another, and how much to trust that comparison.

These rankings are algorithmic approximations for educational purposes only. They are not laboratory measurements and are no substitute for professional acoustic testing or OSHA/NIOSH occupational noise guidance. Peer-reviewed testing has found no suppressed centerfire rifle configuration reliably below the hearing damage threshold at the shooter’s ear. Always use proper hearing protection when firing any firearm, suppressed or not.

Ballistic Coefficients

Where a manufacturer publishes a ballistic coefficient we use it. Most hunting, defensive, and house-brand loads don't publish one, so those use a value typical of the bullet's construction, flagged as an estimate wherever it appears. Be aware that advertised BCs often run optimistic — some bullets measure meaningfully lower in the field than on the box, and the gap widens past roughly 600 yards as the bullet slows. Treat every trajectory here as a starting point for confirming on paper, not a substitute for it.

Exterior Ballistics

Trajectory, drop, wind drift, and energy figures are computed estimates based on a standard point-mass ballistic model and the inputs you supply. Actual performance varies with atmospheric conditions, chronograph accuracy, and firearm/ammunition variance. Verify zero and trajectory data at the range before hunting or competition use.

Reloading Data

This tool does not calculate chamber pressure and never generates a charge weight from first principles. Any future custom-load feature is constrained to interpolation between published load-data points and must never be the sole basis for a handload. Always verify any load against current published data from the powder and bullet manufacturer, start at the published starting load, and never exceed a published maximum charge.

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Configurations involving suppressors, or a barrel under 16" paired with a shoulder stock (SBR), require ATF approval (Form 1 or Form 4), a background check, and an approval wait period before assembly or possession. As of January 1, 2026, the associated $200 federal tax was eliminated by federal law; the registration, background-check, and approval process itself was not eliminated and remains fully in effect. Verify current law in your jurisdiction — you are solely responsible for completing all required legal steps.

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