The Stern Defense .45 ACP Barrel (brand part number 00645ACPBARREL161INCHD) is a 16.1-inch AR-15 barrel machined from 4150 chrome-moly steel and finished with a durable Melonite coating for corrosion and wear resistance. Made in the USA with a 1:16 twist tuned for standard .45 ACP bullet weights, it’s threaded .578-28 to accept muzzle devices sized for the caliber. Builders should note that a .45 ACP AR-15 upper requires an enlarged ejection port, and Stern Defense recommends an 11-ounce buffer or heavier when running a carbine spring for reliable function.

Key Specifications

• Chambered in .45 ACP.
• Measures 16.1 inches in barrel length.
• Threaded .578-28 for .45-caliber muzzle devices.
• Rifled with a 1:16 twist rate.
• Machined from 4150 chrome-moly steel.
• Finished with a Melonite coating for corrosion resistance.
• Made in the USA.
• Requires an 11-ounce buffer or heavier when paired with a carbine spring.
• Needs an enlarged ejection port on the AR-15 upper.

Frequently Asked Questions

Do I need a special buffer for this barrel? Yes, use an 11-ounce buffer or heavier when running a carbine spring.

Does my upper need any modification? Yes, .45 ACP AR-15 uppers require an enlarged ejection port.

What thread pattern does the muzzle use? .578-28.

Buy the Stern Defense .45 ACP AR-15 Barrel

Build a .45 ACP AR-15 upper on a barrel made and coated for durability in the USA. Order it from our Stern Defense lineup, part of our AR-15 barrels selection, at our Lubbock, Texas gun shop for fast, direct shipping.