▶What is the best all around caliber for an AR-15?
5.56 NATO for live-fire capability, but .22 LR conversion for high-volume training. .22 LR has negligible recoil, extremely low cost, and uses the same manual of arms as your 5.56 rifle. Train fundamentals with .22 LR, validate with 5.56. For single-caliber use, 5.56 NATO is unmatched in availability, cost, and versatility.
▶Are 223 and 5.56 the same caliber?
Nearly identical but not interchangeable in all chambers. Both use .224-inch bullets, but 5.56 NATO operates at higher pressure (58,000 psi vs 55,000 psi) and has a longer throat. You can safely shoot .223 Rem in a 5.56 chamber, but never shoot 5.56 in a .223-only chamber. .223 Wylde chambers handle both safely.
▶Is 5.56 or 300 Blackout better?
5.56 is better for general use: cheaper ammo, flatter trajectory, and better terminal performance at range. 300 Blackout only makes sense if you're running suppressed with subsonic ammo. Supersonic 300 BLK is ballistically inferior to 5.56 at every distance.
▶What is the best AR-15 caliber for home defense?
5.56 NATO with quality defensive ammo (77gr TMK, 62gr TBBC) is the best choice. It fragments reliably in soft tissue while reducing over-penetration risk. 300 BLK subsonic is quieter suppressed but requires perfect shot placement due to lower velocity.
▶Is 6.5 Grendel worth it?
Yes, if you need AR-15 capability past 500 yards. 6.5 Grendel retains energy far better than 5.56 and offers genuine 800+ yard capability from a standard AR-15 lower. Downsides: expensive ammo ($1-2/round), limited magazine capacity, and specialized bolt required.
▶What caliber AR-15 for hunting?
For deer-sized game: 6.5 Grendel (best ballistics), 300 Blackout (short range/suppressed), or 6mm ARC (flat shooting). 5.56 is marginal for deer and illegal in some states. For hogs/varmints, 5.56 with quality expanding ammo works well.
▶Can I shoot 5.56 in a .223 chamber?
No: 5.56 NATO is loaded to higher pressures than .223 Rem. Shooting 5.56 in a .223-only chamber risks dangerous overpressure. .223 Wylde chambers safely shoot both. Always check your barrel markings before loading.
▶What is the effective range of 300 Blackout?
Supersonic 300 BLK: ~300 yards effective. Subsonic 300 BLK: ~100 yards max for reliable expansion. The cartridge was designed for CQB suppressed use, not long-range shooting. For distance work, stick with 5.56 or move to 6.5 Grendel.
▶Which is more powerful, 5.56 or 300 Blackout?
It depends on distance and barrel length. At the muzzle from a 16" barrel, 5.56 produces ~1,300 ft-lbs vs 300 BLK supersonic at ~1,350 ft-lbs, roughly equal. But 5.56 retains energy far better at range due to higher velocity and better ballistic coefficient. At 300 yards, 5.56 still carries ~500 ft-lbs while 300 BLK drops below 400. For suppressed subsonic use, 300 BLK delivers ~500 ft-lbs at the muzzle with heavy 220gr bullets. Different tools for different jobs.
▶What is the advantage of 300 Blackout?
The primary advantage is suppressor performance. 300 BLK with subsonic ammo through a quality suppressor is hearing-safe and extremely quiet. It also performs well from short barrels (8-10"), losing less velocity than 5.56 from SBR-length barrels. It uses the same lower receiver, bolt, and magazines as 5.56, so you only need a barrel swap. For dedicated suppressed SBRs, nothing in the AR-15 platform matches it.
▶What are the drawbacks of 300 Blackout?
Cost is the biggest drawback: 300 BLK runs $0.75-1.50/round vs $0.35-0.50 for 5.56. Ammo availability is also worse, especially in rural areas. Without a suppressor, supersonic 300 BLK offers no meaningful advantage over 5.56 while costing twice as much. The most dangerous drawback is the cross-chambering risk: a 300 BLK round will chamber in a 5.56 barrel and cause catastrophic failure when fired.
