Calibers & Configurations Guides
5.56, .300 BLK, .224 Valkyrie, and more, matched to your build.
6.5 Grendel vs .308 Winchester: AR-15 vs AR-10 for Hunting
6.5 Grendel keeps you on the AR-15 platform, .308 requires an AR-10. Here's how they compare on ballistics, hunting, recoil, and cost.
More Calibers & Configurations Guides
.458 SOCOM vs .50 Beowulf: Big Bore AR-15 Cartridges Compared
.458 SOCOM and .50 Beowulf both turn an AR-15 into a big-bore thumper. Here's how they differ on ballistics, recoil, ammo, and cost.
Best .224 Valkyrie Uppers: Long-Range 5.56 Alternative
.224 Valkyrie was built to keep 90 grain bullets supersonic to 1,300 yards. Here's where it still shines and the best uppers you can buy.
Best 6mm ARC Uppers: The Modern Long-Range AR-15 Cartridge
6mm ARC delivers 6.5 Grendel ballistics with less recoil in a standard AR-15 platform. Here are the best complete uppers and what to look for.
5.56 NATO vs .223 Wylde vs .223 Remington: The Chamber Guide
5.56 NATO, .223 Remington, and .223 Wylde look identical on the outside but chamber differently. Here's what that means for pressure, accuracy, and safety.
.350 Legend Upper Guide: Straight-Wall Hunting on the AR-15
How to pick a .350 Legend upper: barrel length, twist rate, compatibility with your existing AR-15, and why straight-wall states drove this cartridge into the mainstream.
6.5 Grendel vs. 6mm ARC: Which Long-Range AR-15 Wins?
Head-to-head comparison of 6.5 Grendel and 6mm ARC on the AR-15: ballistics, effective range, ammo cost, and which one fits your build.
.300 Blackout vs. 5.56 NATO: Which Upper Should You Build?
Head-to-head comparison of .300 Blackout and 5.56 NATO uppers: ballistics, barrel length, suppressor use, ammo cost, and which one fits your build.
AR-15 Barrel Length Guide: 7.5, 10.5, 14.5, 16, and 20 Inch Compared
AR-15 barrel length comparison: velocity, gas system pairing, legal classification, and use-case recommendations for 7.5, 10.5, 14.5, 16, and 20 inch barrels.
AR-15 Gas System Lengths Explained: Pistol, Carbine, Mid-Length, and Rifle
How AR-15 gas system lengths work: pistol, carbine, mid-length, and rifle compared, with dwell time, felt recoil, and barrel pairing explained.
AR-15 Upper Calibers Compared: Which One Fits Your Build?
Compare the eight most common AR-15 upper calibers side by side, from 5.56 NATO to .50 Beowulf, with velocity, energy, effective range, and cost per round.