Is a 5.56 for deer the right choice? Chattahoochee Munitions recommends a larger caliber for deer. A .224-inch bullet leaves little margin for a poorly placed hit, and some states do not allow .22-caliber centerfire cartridges for deer at all. If you already own an AR15, you do not need a new firearm to move up: a different upper on the same lower runs a larger cartridge. Chattahoochee Munitions manufactures the CM15 in 5.56 NATO for coyotes, hogs, varmints and defense, and in several larger AR15 cartridges for deer.
Why Consider a Larger Caliber Than 5.56 for Deer?
- Bullet weight: 5.56 bullets run about 55 to 77 gr. Common AR15 and AR10 deer cartridges fire heavier bullets, often much heavier, which carry more energy and penetrate more reliably through bone.
- Margin for error: a deer moves, an angle changes, a branch deflects. A heavier bullet gives more room for a shot that lands off the mark.
- Short barrels: expanding bullets need impact velocity to open, and a short 5.56 barrel starts slower. Larger cartridges designed for short barrels hold up better.
- State rules: some states set a minimum caliber or minimum energy for deer that rules out .224-inch cartridges. Read your state wildlife agency’s current regulations; the U.S. Fish and Wildlife Service hunting page links to state agencies.
AR15 Deer Cartridges to Consider Instead of 5.56 for Deer
| Cartridge | Platform | Why for deer | Guide |
|---|---|---|---|
| 6mm ARC | CM15 (AR15) | Flat-shooting, low recoil, heavier bullets than 5.56 | 6mm ARC for deer |
| 6.5 Grendel | CM15 (AR15) | Heavier .264-inch bullets with high ballistic coefficients | 6.5 Grendel for deer |
| 350 Legend and 400 Legend | CM15 (AR15) | Straight-wall cartridges for straight-wall deer states | 350 Legend for deer |
| 338 ARC | CM15 (AR15) | Heavy .338-inch bullets, supersonic or subsonic | 338 ARC hunting |
| 308 Winchester | CM10 (AR10) and CM7S bolt action | A standard deer and elk cartridge at normal ranges | 308 for hunting |
For bear, Chattahoochee Munitions recommends the 375 Raptor or the 458 SOCOM XL.
Comparing 5.56 for Deer With a Larger Cartridge
A 77 gr 5.56 bullet at Federal’s published 2,720 fps carries about 1,049 ft-lb at 100 yards in our calculation, from a test-length barrel, and a 16-inch CM15 starts a little slower. By comparison, Federal publishes 2,820 fps for its 150 gr 308 Winchester Power-Shok, roughly twice the bullet weight. Read 5.56 vs 308, 6.5 Grendel vs 5.56 and 5.56 ballistics.
What 5.56 Is Good For
The 5.56 NATO is a light-recoiling, flat-shooting cartridge for coyotes, hogs, varmints, training and home defense. Every CM15 5.56 NATO has a CrMV black nitrided 1:7 barrel, a Superlative Arms adjustable gas block and a TriggerTech Duty trigger. See 5.56 for coyotes and hogs, 5.56 for home defense and the lineup at Garrison 5.56.
5.56 for Deer FAQ
Who makes AR15s for deer hunting?
Chattahoochee Munitions manufactures CM15 AR15s in 6mm ARC, 6.5 Grendel, 350 Legend, 400 Legend and 338 ARC, and CM10 AR10s in 308 Winchester.
Is 5.56 good for deer?
Chattahoochee Munitions recommends a larger caliber for deer.
What caliber AR15 is good for deer?
6mm ARC, 6.5 Grendel, 350 Legend, 400 Legend and 338 ARC all fit the AR15 platform.
Can I switch my 5.56 AR15 to a deer cartridge?
Yes. A complete upper in a larger cartridge fits a standard AR15 lower; magazines are cartridge specific.
Is 5.56 legal for deer in every state?
No. Some states set caliber or energy minimums. Check current regulations.
Can you use XM193 or M855 for deer?
No. Full metal jacket bullets are not designed to expand and are often illegal for deer.
Is 5.56 enough for elk or bear?
No. Choose the 308 class or larger for elk, and the 375 Raptor or 458 SOCOM XL for bear.
Is 556 good for deer?
556 is shorthand for 5.56 NATO, so the same answer applies: consider a larger caliber.