Daniel Defense Big Hole Upper Receiver for Large Pin Lowers

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Daniel Defense Big Hole Upper Receiver

Made for large pin lowers and perfect for upgrading old Colt lowers

Daniel Defense just has a way of making great receivers. These are hard coat anodize with a superb finish. If you are used to military uppers, you will drool over this. Not the military scuffing that you see with Colt, Knights, and others. All of those are some of our favorites, but for a civilian rife, it really does not get better. The finish is a uniform black anodizing. The Daniel Defense brand is located on the upper left of the left side of the receiver.

The Daniel Defense Big Hole Flat Top Upper has a .315" front pin hole specifically to mate with early Colt lowers with .315" front holes. No more do you need to mess with offset adapters and screw together assemblies. Including all hardware and a .315" ball detent push pin, this is just the upper needed to upgrade vintage Colts.


  • Factory new from Daniel Defense
  • 7075-T6 Aluminum
  • Mil-spec Type III Hardcoat Anodized
  • M4 Feed Ramps
  • T-Marks
  • Ejection Port Cover
  • Forward Assist
  • DD Logo Laser Engraved on Left Side
  • Made in the USA!
  • Manufactuer's Part Number:  04-012-09001

What is a Large Pin Upper, and Do I need it?

The AR-15 platform, particularly from Colt, underwent several changes since its inception, creating a distinction between older and newer models. Among these changes, the pivot pin size that connects the upper and lower receivers is particularly significant, a feature that especially marks Colt rifles produced from the late 1980s to the mid-1990s. Initially, Colt utilized a larger pivot pin (0.315 inches in diameter), commonly referred to as the "large hole" receiver, in models such as the SP1 and some AR-15A2 rifles. This was a deviation from the industry-standard small pin (0.250 inch in diameter), contributing to a unique challenge for shooting enthusiasts looking to upgrade or modify their firearms.

Individuals passionate about shooting, with an eye toward optimizing their older Colt AR-15 rifles for modern performance standards, often consider upgrading to a flat top M4 upper receiver. This upgrade offers enhanced versatility and accuracy, allowing for the mounting of modern optics and sights. However, due to Colt’s original large pivot pin design, standard small hole upper receivers cannot directly mate with these vintage Colt lower receivers. Therefore, firearms enthusiasts aiming to enhance their older Colts must seek out special large hole upper receivers specifically designed to accommodate the larger pivot pin size or alternatively use adapters that bridge the size discrepancy. This necessity for compatibility underscores the importance of understanding the nuances within Colt’s evolution to properly honor and upgrade these esteemed firearms.