Improved Sling for the Carbine

January 2016-F

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REPORT OF THE INFANTRY BOARD #1666, IMPROVED SLING FOR THE CARBINE
by Marty Black

The carbine’s sling went through some minor changes during WWII. Among the approximately 12
manufacturers, some variation exists in color, thickness and weave of material, contour of the C-shaped
end tabs (tips), and the size and shape of the buckle.

However, some general statements can be made: The earliest slings varied in color: tan, very light
green, or a dull mustard/bronze color, with thin C-shaped end tabs and a very narrow buckle that was
extremely difficult to adjust. The color of the sling changed to a more consistent khaki/light green, and
then a dark OD green beginning in late 1943 - early 1944. The C-shaped end tabs were made stronger
and slightly thicker. Inexplicably, the opening in the sling well of the stock was never made larger to
accommodate the thicker slings, making it very difficult to attach and remove the later slings from the
carbine.

Sometime after the end of the war, probably during the Korean War of 1950-1953, the shape of the end
tabs was changed to a solid D-shape, making the sling nearly identical in construction to that used by the
Marines on their Reising submachine gun. This change made it even more difficult to push the sling
through the sling slot and around the oiler of the carbine stock.

The Infantry (Test) Board at Fort Benning, Georgia released a report on 23 August 1944, detailing the
testing of an “improved” sling for the carbine, which used the hardware from the canvas M1 Sling “to
eliminate the difficulties encountered in adjusting the standard sling.”

It appears that the test board was confused about encountering both types of carbine sling buckles,
which were described as ‘slip buckles’ and ‘slip lock buckles’ throughout this report. “Standard carbine
slings obtained at Fort Benning were equipped with one of two sizes of slip buckles…At one time in the
past, a larger slip lock buckle was used on the standard sling. If this was before the introduction of the
smaller slip buckle, it is apparent that the adoption of the smaller slip lock buckle was a mistake.
However, if the larger slip buckle was introduced after the smaller slip buckle, then it is apparent that the
deficiency of the smaller slip lock buckle was recognized, and the problem has been solved in a most
efficacious manner.”

It is not known if the slings with the “smaller slip buckles” were NOS (new, old stock), or whether one
or more subcontractors were still producing slings with these buckles in 1944.



A. End of Standard Sling, which is looped through upper sling swivel.
B. End of Improved Sling, which is attached to upper sling swivel.
C. End of Standard Sling, which is looped through lower sling swivel. Note the (small) three bar
slip lock buckle.
D. End of Improved Sling, which is looped through lower sling swivel. Note quick release type
buckle.

Note in figure B, that a “metal snap fastener” from an M1 Sling has been sewn on. The “quick release
type buckle” in Figure D is also from the M1 Sling.

The description of the photo above buckle and large three bar slip lock buckle.”
Several tests were conducted to determine if the Improved Sling was a
large enough improvement over the Standard Sling to warrant adoption.


The last two tests comprised “24 hours of continuous adjustment, with even and jerky tension, wet and
dry”…followed by “24 hours of repeatedly installing the slings, adjusting them, then removing the
slings from the carbines.”



The results: “The female component of the lift-the-dot fastener on the standard sling became weak, but
upon completion of the test was still effective. The metal tip of the lower end of the sling came off in
the seventeenth hour (of the latter test). There was very little evidence of wear on the web…

The hardware of the subject sling (improved sling) showed no wear. The loose end portion of the web
upon which the quick release buckle slides began to show extreme wear and fraying in the nineteenth
hour (of the latter test). At the end of the twenty-fourth hour, it was shredded. The quick release buckle
was, however, still fairly effective in locking the web.

The Infantry Board concludes:
1. That there is no military requirement for any change from the slip buckle type adjustment of the
carbine sling to another type, nor for any change from the standard method of attachment of the
sling to the carbine.
2. That the small slip buckle, although very effective in locking, is needlessly difficult to operate
when making sling adjustment.
3. That the larger slip buckle is the most desirable size and is the most satisfactory buckle for the
carbine sling.
4. That the subject Improved sling presents no essential advantage over the standard carbine sling
sufficient to warrant a change to the former.
5. That the smaller slip buckles, although more difficult to operate, should be used until the supply
is exhausted, and then replaced by the larger slip buckle.

The Infantry Board recommends:
1. That no further consideration be given to the Improved (subject) carbine sling.
2. That the larger size slip buckle, if not already standard, be made standard for use on the standard
carbine sling.
3. That stocks of the small slip buckle be used until stocks are exhausted, and thereafter replaced
with the larger size.”

Wonder if the D tip cap coming off led to a design change?

When I was in Nam in 66, there were several M2 carbine in use. These had the M1 Garand stle slings. I could only find 1 photo of one showing the adjuster. 

Say wd4ngb,

I forgot to ask earlier, Is that YOUR photo next to your user-name alongside your post? Were you in MACV?

If so, the Carbine Club made you famous (ha!) by putting you on the cover of our Newsletter 376 in October 2013.

Regards, Marty Black

This sling is like the M1 Garand style sling, but 1 inch wide like the Carbine's sling. I liked it so much better for shooting, so made a little page about it, and where you can get one.

There is a section on it about the history of the sling, with your research, with credit of course. :)

For sure! Pls post some closeup photos!   We'd love to see those slings. Thanks in advance, Marty Black