E) Pre-’94 ban mainland Chinese magazines work great. They have three dimples
around the magazine catch slot and are gray (not charcoal) in color. They were packed in
cosmoline from China. AFAIK, none have been imported since 1994 into the United
States.

F) Genuine Taiwanese T57 magazines work great. These were imported into the United
States in the early 1990s. Features are consistent so don't get fooled by the mysterious
origin blued magazines.

Taken From: Pictorial M14 Magazine Identification Guide

and............

Chapter 12: Taiwan T57 Magazines

Excerpt from M14 Rifle History and Development Third Edition:

Foreign Manufacture Magazines

Taiwan and People's Republic of China also produced twenty round magazines that were
imported from the late 1980s until 1994. Some Chinese twenty round magazines were
blocked to five rounds capacity by welding a metal block under the follower following the
1989 import ban. Such magazines were included in the shipping boxes for Chinese M14
rifles imported by Century Arms International and IDE USA. While Chinese magazines
are narrower than the USGI magazines, they have an excellent reputation for reliability.
Chinese magazines imported into the United States in the 1980s and 1990s were coated
with grease. Chinese magazines imported into Canada after 2000 were preserved with
oil and packed in heat-sealed transparent plastic bags. Canadian plastic twenty round
magazines have also been imported into the United States. These magazines have a
good reputation but may require a small amount of plastic to be removed from the locking
tab to feed reliably.

Taiwanese T57 Blued Finish Magazines

From Nolan,

The pair of T57 blue finish magazines that I used for these pictures was purchased new in
the early 1990's in faked USGI packaging from a large dealer on the West Coast.
Like the matte finish ones, there are a total of either twelve or thirteen spot welds on the
front spine of the magazine. I have examples of both. Eleven or twelve are below the
front side catch slot and one is to the side of it. It is very similar to the USGI method of
construction except that it looks like Ray Charles did the spot welding and the welds are
typically smaller in diameter with burn pits that you don't see on USGI magazines.
The T57 magazines also have drain holes that measure smaller than any of the other
brand magazines I've measured. They only measure .170 to .172 or an inch or so in
diameter. They're ten to fifteen thousandths smaller than the mainland Chinese "Norinco"
magazines. Another thing I've noticed about the blued version is that there's often copper
colored discoloration around the drain hole.
The followers are also stamped differently than the "Norinco" magazines. I feel confident
that they were not made on the same tooling. Most noticeable is the top rear "corner" of
the follower where it contacts the bolt stop. All of the T57 magazines I've looked at have
a rounded corner here rather than a squared off one. This can keep some rifles from
locking open on the last shot.

and.....................

Taiwanese T57 Matte Finish Magazines

From Nolan,

The pair of T57 matte finish magazines that I used for these pictures was purchased new
in the early 1990's in faked USGI packaging from a large dealer on the West Coast.
There are a total of either twelve or thirteen spot welds on the front spine of the
magazine. I have examples of both. Eleven or twelve are below the front side catch slot
and one is to the side of it. It is very similar to the USGI method of construction except
that it looks like Ray Charles did the spot welding and the welds are typically smaller in
diameter with burn pits that you don't see on USGI magazines.
With the dull matte finish, and the spot weld pattern on the front spine, and around the
front catch slot, I suspect that a lot of these are in the hands of people that think that they
are unmarked USGI.
The T57 magazines also have drain holes that measure smaller than any of the other
brand magazines I've measured. They only measure .170 to .172 of an inch or so in
diameter. They're ten to fifteen thousandths smaller than the mainland Chinese "Norinco"
magazines.
The followers are also stamped differently than the "Norinco" magazines. I feel confident
that they were not made on the same tooling. Most noticeable is the top rear "corner" of
the follower where it contacts the bolt stop. All of the T57 magazines I've looked at have
a rounded corner here rather than a squared off one. This can keep some rifles from
locking open on the last shot.


Taken From: Pictorial M14 Magazine Identification Guide

2007 Fake “T57” Magazine
This magazine was sold by firearms accessories dealers from 2005 into 2008. Many
buyers report reliable service with these magazines. They were marketed as unissued
1970s vintage units made in Taiwan. The claim is also made by more than one purveyor
that these magazines were made in Taiwan with former Harrington & Richardson M14
project equipment. The truth is that the machinery necessary to produce genuine T57
magazines and flash suppressors was not supplied to the Taiwan government.
Therefore, the State Arsenal had to find machinery in Taiwan to produce these parts.
Per the 1967 Memorandum of Understanding with the U. S. government, T57 rifles,
accessories and parts had to be interchangeable with their USGI counterparts. The
government of Taiwan was provided with a complete set of U. S. government drawings
and inspection gauges for its T57 project. Examination of the fake “T57” magazines
shows that they do not meet a number of M14 magazine component drawing and quality
assurance requirements. For example, the latch plate pattern of three dimples does not
match any of the specified weld patterns of USGI drawing D7790197. The fake “T57”
magazines are coated in oil and wrapped in brown wax paper secured by a rubber band.
That doesn’t look like modern military parts packaging.

Taken From: Pictorial M14 Magazine Identification Guide