sequence of production of Colt 20 round magazines

[RCS]

I am attempting to put together the correct sequence of production of the Colt AR-15/M16 magazines

note: the early COLT..223 magazine has the smaller letters/number than the later COLT..223 magazines

the early Colt .223 magazine has the five round block430964309743098

[lyman]

I thought the 5 or 10 round block was done during the ban era only?

[RCS]

The 1965 era Colt SP1 semi auto came with the early magazines with the small white dot. These magazines had a part put inside
by the factory so that the magazines only held five rounds (for hunting in most states). This part could be removed by taking
the magazine floor plate off

The 1966 Gun Digest page 302 lists the Colt AR-15 Sporter Carbine and states magazine blocked to 5 rounds

[BEAR]

Yep, I bought a SP1 in '71 that had 2 blocked magazines. The instruction booklet told you how to remove the spring steel block by taking off the floor plate. Only installed for hunting purposes much like the wooden dowel in my Mossberg limiting number of rounds to three.

BEAR

[jjrothWA]

Got one from early 90's blocked with the "U-shaped" folded flat stock, held in with a couple "pop" rivets.

Didn't stay that way, after getting home!

Did purchase an new-made plastic for hunting, just have to insert into well and push the back pin , then load with five rounds, for when using for deer / coyotes.

[RCS]

I found these photos on the internet that show the Colt AR-15 chambered for the 222 Remington
cartridge (export to countries that ban the 223/5,56mm military calibers). The early Gun Digest
had these listed too.

note the Colt magazines have rivets attached to the magazine block (these can be removed)4333643337

[hvymech]

I found two 20 round Colt mags marked .223 at the Tulsa gun show for $15.00 each, that makes 8. Still looking.... hvymech

[RCS]

Early magazines had the small COLT..223 CAL while the later had the larger COLT..223 CAL