Part of the AR’s ingenious design lies with two pins: the takedown pin and the pivot pin. Pop out these two pins and the upper receiver can be removed and swapped, allowing a user to instantly change the caliber of an AR, or for specific needs like CQB or long-distance shooting, reduce or increase barrel length, respectively.
- RELATED STORY: Uppers From the Black Guns 2015 Buyer’s Guide
- RELATED STORY: Top 20 Next-Gen Piston-Driven ARs
For more information on the AR uppers listed in the gallery above, please visit the following websites:
- Armalite M-15 Target: armalite.com; 800-336-0184
- BCM Uppers: bravocompanyusa.com; 877-272-8626
- Daniel Defense M4v11 Pro Series Upper: danieldefense.com; 866-554-4867
- DSI 16-Inch Typhoon: dark-storm.com; 800-963-7700
- Del-Ton AR-15 16-inch Pre-Ban Flat Top: del-ton.com; 910-645-2172
- POF-USA P15 Puritan Upper: pof-usa.com; 623-561-9572
- Precision Reflex 18-inch Mark 12 Mod 0 SPR Gen II: precisionreflex.com; 419-629-2603
- Primary Weapons Systems MK214 Upper: primaryweapons.com; 208-344-5217
- Rock River Arms Lightweight XL: rockriverarms.com; 309-792-5780
- Safety Harbor SHTF 50 Single Shot Upper Conversion: safetyharborfirearms.com; 727-726-2500
- Seekins Precision Combat Billet: seekinsprecision.com; 208-743-3400
- Sig Sauer M400 Upper: sigsauer.com; 603-610-3000
- Smith & Wesson M&P15TS Upper: smith-wesson.com; 800-331-0852
- Stag Arms Model 3TH-M Upper: stagarms.com; 860-229-9994
- VooDoo Innovations Ultra Lite: 813-867-4242; voodooinnovations.com
- X Products Can Cannon: xproducts.com; 844-770-7765
- X Products X-15 Billet SCU: xproducts.com; 844-770-7765
- Yankee Hill Machine KR7 Series: yhm.net; 877-892-6533




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