Didja Know

Did you know that there's no actual mil-spec for the M1911A1 any more?

The M9 is MIL-P-48655.

The M11 is MIL-P-71012.

The M1911A1 pre-dates the mil-spec system and was given a number much later, that number was superseded at least three times.

There's a Federal Specification for the M1911A1, D-P-355a from 16Sep64 which superseded D-P-00255 of 07Dec61 which superseded MIL-P-1297B of 01Jan60 which superseded MIL-P-1297 of ???   It refers to a set of drawings made in 1928 and a number of later military standards and is very mil-spec in its format.

I don't have the measuring tools to check everything, but I am curious to see how many 1911 makers today adhere to those 1928 drawings.

D-P-355a 3.3.2 states, "Interchangeability. Unless otherwise specified on the drawings, all parts shall be interchangeable. Pistols and repair parts shall be capable of meeting the interchangeability tests specified in 4.3.3.4 and 4.4.4 (In normal assembly operations there shall be no objections interposed to preferential assembly of parts provided that all parts are dimensionally acceptable.)"  Try that with a Colt and a Kimber!

4.3.3.4 and 4.4.4 are fascinating reading!

Of note is reliability.  D-P-355a has two 2,500 round tests.

Zero failures for the entire 5,000 rounds are allowed for

Malfunction
Disconnector fails to function
Failure of sear to release
Failure to extract
Failure to close
Faulty trigger pull
Grip safety fails to function
Light blow
Magazine catch fails to function
Primers, setback
Safety lock fails to function
Slide stop fails to function
Uncontrolled fire

Breakage
Barrel lug, broken or burred
Extractor, broken or burred
Ejector, broken or burred
Firing pin hole, enlarged
Link, broken
Locking lugs, chipped or burred (barrel or slide)
Springs, broken or set

Magazine failures
Bent side walls
Bent or cracked lips
Inability to load seven rounds
Other magazine failures.

In the first 2,500 rounds you're allowed:

1 Failure to eject
1 Misfire
1 Pierced primer
2 Other malfunctions and nonacceptable conditions
1 Other broken part

In the second 2.500 rounds you're allowed:
2 Failure to close
1 Misfire
1 Pierced primer
4 Other malfunctions and nonacceptable conditions
1 Broken firing pin
2 Other broken parts
1 Failure to feed (due to follower)
1 Follower distorted

Thanks to Daniel Watters for the correction!