40+ year old US Army specs and current (post 1984) Springfield Armory consumer 1911 specs are two different animals,
But the sights were the same geometrically and dimensionally...as are the sights on the GI Mil-Spec. On the others, I never bothered to run a ratio to see if they theoretically zeroed the same...but the early 1991A1 Colts that I bought back in the day zeroed at 50 yards...believe it or not...and that puts it around 2 inches high at 25.
especially since the current Springfield company is not the same as the Springfield Co that supplied 1911's to the US Army. They've been privately owned since 1974, and a totally different and distinct company.
They were never the same outfit, other than in name. The Geneseo-based Springfield was created...not bought...when the real one closed its doors. The Massachusetts-based Springfield Arsenal made muskets for George Washington and company.
Springfield's owners manual states they are 6:00 hold @ 25 yards.
And there ya go. A 6 O'Clock hold on a 4-inch bull that finds a center POI is zeroed at 50 yards...like it or not/believe it or not... assuming that the barrel tilt at the rear is to spec.
If a 5-inch 1911 copy or variant with fixed sights doesn't zero at 50 yards...somethin' is all fugasi...either the sights or the vertical barrel engagement.
But, I've only been dancin' with Johnny's Toy for about 50 years...so what would I know?
Anyhoo...back to the low shootin' Commander.
Because of the shorter sight radius and slightly greater degree of barrel tilt, it's no surprise that it shoots low at 21 feet. At that point...even assuming a 25-yard zero...the bullet is on the rise and hasn't yet reached the first intersection with the line of sight. They all zero twice. Once when the bullet is on the rise, and the second time at distance, after the bullet has dropped from its mid-range trajectory...or its highest point within the arc of its trajectory with a given zero distance. Sometimes referred to a "Maximum Point Blank Range" it describes a theoretical zero in which the bullet neither rises nor falls outside of an 8-inch circle with a center hold. The US military calls it the "Battlesight" zero.