Pro2A Tactical Big Bore AR-15 Complete Uppers, Rifles & Pistols
Pro2A Tactical Big Bore AR-15 Complete Uppers, Rifles & Pistols
Massive Stopping Power. Zero Compromise.
When standard intermediate calibers aren't enough, step up to the devastating performance of Pro2A Tactical’s Big Bore lineup. Engineered for modern sporting hunters, brush country defense, and deep- woods tracking, our straight-wall and large-bore AR-15 configurations deliver massive knockdown power out of standard-sized lower receivers.
From ultra-compact thumpers to extended hunting setups, our direct-to-consumer big-bore platforms are precision-built right here in Georgia to out-perform mass-market mass production.
Why Choose Pro2A Tactical Big Bore Builds?
True Left-Hand Ejection Available: You shouldn't have to catch hot, oversized brass in your face. We are one of the few custom manufacturers offering fully mirrored left-handed uppers and full-auto cut left-hand BCGs across our entire big-bore caliber lineup.
Enlarged Ejection Ports: Avoid frustrating cycle failures. Our big-bore upper receivers feature custom-widened ejection ports engineered explicitly to clear heavy .458 SOCOM, .450 Bushmaster, and 12.7x42 (.50 Beowulf) brass cleanly without marring or stovepiping.
Tuned Gas & Cycle Control: Big cartridges require precise gas management. Our builds utilize optimized gas ports, or optional adjustable low-profile gas blocks, allowing you to dial in your rifle to perfectly match heavy subsonic hunting loads or standard supersonic rounds.
Custom Feed Ramp Geometry: To combat common big-bore magazine and single-stack feeding drag, our barrels feature hand-polished, wide single-feed ramps to ensure seamless chambering with every pull of the trigger.
Direct Manufacturer Value: Skip the distributor markups. We assemble, test, and ship your rifle or upper group directly from our facility to your FFL, providing duty-grade specifications at competitive boutique pricing.
Explore Our Big-Bore Caliber Lineup
458 SOCOM Uppers & Firearms
Developed for close-quarters stopping power, the .458 SOCOM throws heavy-grain slugs with tremendous muzzle energy. Optimized with fast-twist barrel options, our uppers excel when paired with a suppressor or run on a high-speed reset trigger setup. Available in hard-hitting 8.5" and 10.5" pistol configurations or traditional 16" hunting lengths.
12.7x42mm (.50 Beowulf Compatible)
The ultimate semi-automatic sledgehammer. Throwing a true half-inch diameter projectile, our 12.7x42mm systems deliver unparalleled hard-target disruption. Built with heavy-duty bolt faces and robust extraction systems to ensure reliability shot after shot. [1]
Need to meet strict straight-wall cartridge regulations for deer season? Our .350 and .400 Legend rifles give you bolt-action accuracy with semi-automatic speed. They offer minimal recoil compared to the heavy thumpers, making them incredibly flat-shooting and high-velocity choices out to 200+ yards.
450 Bushmaster
The "Thumper" classic. Perfect for medium-to-large game tracking, our .450 Bushmaster uppers utilize high-grade Melonite-finished barrels and premium muzzle devices to minimize recoil while maximizing down-range energy transfer.
Technical Build Tips & Compatibility
Magazine Setup: While big-bore calibers stack single-file into standard 5.56 magazines, we highly recommend using dedicated big-bore single-follower magazines (like Duramag or modified Lancer magazines) to guarantee high-reliability feeding.
Buffer Recommendations: Because large-bore rounds generate a aggressive recoil impulse, we build our complete firearms with heavy H1 or H2 buffers to ensure smooth cycling and structural longevity.
Muzzle Accessories: Ensure any flash cans, linear compensators, or suppressors are explicitly rated for a minimum bore size of .458 or .50 depending on your respective build
