2021-D

Carbine of Interest

Inland Serial Number 270

Inland 270 recently came into possession of one of our members, Major General Hammer Hartsell, USMC Retired.

The carbine as received has retained some very interesting parts from the earliest days of Inland production which makes this carbine of interest “newsworthy.”

The stock group has been replaced, most likely due to the original breaking. The hammer has also been updated with a straight hammer. The trigger and sear show signs of polishing. This combined with the late hammer suggests it was to improve the trigger pull.

The barrel is dated 5-42 which is the earliest barrel used on production Inland carbines.

The Receiver is consistent with the early Inland receiver features. The left side rear detail has a 9/16” long leg. The trigger housing lug is a type 1.

The slide guide has only the forward notch. Notice how there is a slight machining error to the rear of the notch. The forward notch had a critical dimension as this was used to dismount the slide. The machining tool would enter and exit this hole to mill the slide guideway. The later rear hole allowed the tool to enter and exit to mill the guideway without risking damage to the slide dismount notch.

The rear of the receiver does not have a hole at the back of the operating slide spring housing. At some point during rebuilds, the hole would be added to the early receivers.

Another interesting observation is a round marking on the left side of the receiver. Other very early receivers have also been observed with this marking in various locations on the left side of the receiver.

It is believed to be a hardness test. We normally see punch type markings on some parts which are from a Rockwell hardness test. It is believed this may be a Brinell Hardness test mark, which can measure the lower end of the hardness scale.

The rear sight is a little different in that the 300-yard leaf is slightly longer, and the peephole is also higher. One explanation given was that this was due to the sight being developed for a velocity of 1800 fps.

Inland 270 on left compared to an early Inland production rear sight.

The carbine cartridge was approved on February 14, 1942, there were still issues obtaining a satisfactory propellant, and work continued after the round was adopted. During April 1942 tests were done on commercial and military powders. A new powder was adopted, and this new powder had a velocity of 1900 fps. This sight may be from preproduction for use with the slower powder the longer 300-yard leaf would need to be higher and bring the barrel up. With the higher velocity of 1900 fps, the trajectory changed, and the hole would be lower. 

Inland barrels typically have what we refer to as “hieroglyphics” or “characters” on the barrel flat. It started with very few makings and grew in number. Later the characters changed to letters and numbers. It is presumed that these markings indicate various inspectors.

Here we see this 5-42 barrel does not have any of these characters. There is a serif S near the gas piston and an Ordnance Bomb. This is consistent with very early production. The letter “R” has also been reported.

The early Inlands were observed as a black oxide finish on the barrel, receiver, and trigger housing. The finish would be a dull gray/black on the areas not protected by the stock. Areas under the wood line would retain a blued appearance. This finish across the barrel and receiver appears consistent but not what we would expect to see on an early Inland.

We know from CC Newsletter 363-7 that the Ordnance Department was experimenting with various carbine finishes during 1942.

The Proof P on the barrel would be applied after proof firing on a finished carbine. Notice the P is in the “white”, this finish may have been an alternate finish that Inland tried.

The bolt and T1 firing pin are unmarked. The T1 extractor is unmarked, which has been reported on some early carbines. The earliest known Inland bolts were marked with an OI in a circle on the large lug (although early Winchester bolts were reported as unmarked.) In comparing bolts, the machining on this one is consistent with an early OI in circle bolt.

The face of the bolt has a steeper taper to where the case seats. This gives the bolt a thicker appearance face. The bolt also has a slightly shorter overall length.

The bolt and small parts are blued as expected.

The trigger housing has the early tall Inland logo. It also has the front and rear bevel details which are to be expected in an early Inland.

Notice how the hammer plunger hole is not recessed for the hammer spring. This was changed very early on because the hammer spring would slide around making it difficult to install the hammer spring plunger.

The tip of the hammer spring plunger has what looks like a hand-ground point to it, which has never been reported.

This is most likely an attempt to make assembly easier before the solution of counterboring the plunger hole on the trigger housing

The narrow magazine wall is expected. What is interesting is how tight it sits against the receiver, rather than leaving a small gap as is normally seen. Notice the matching wear marks on the receiver.

From here we find a few unexpected features.

The back wall of the trigger housings has a guideway for the magazine nibs. Due to manufacturing differences between manufacturers, these guideways can be just two short notches (milled) or full-length relief cuts on the back wall (broached).

One of Inland’s contributions to the development of the carbine was to change the design of the trigger housing to make it more symmetrical and easier to produce. With the mag well symmetrical the relief cuts could be broached instead of milled. The broaching process was faster and was the only style reported on production Inland made trigger housings.

However, the back wall of this trigger housing has the milled “notches type” relief cuts for the magazine nibs and is the first report of this feature on an Inland.

Inland in their pre-production did mill the short notches before the trigger housing change. These trigger housings are visually different from those used in production carbines. See WB pg 304.

Also of interest is that there is a “P” in a location where we sometimes see an ordnance bomb.

The slide at first glance looks like a typical “Type II” or an “E168” from the http://www.uscarbinecal30.com/forum/carbine-club-data-sheets_topic26.html" rel="nofollow - data sheet. It is marked PI in a circle inside the box. It has an arm joint of 3/8”. The slide box rear has the part round cut.

The shape of the bolt camming cut is unusual. Look at the right wall by the orange arrow.

On June 8 to 13, 1942, Aberdeen Proving grounds held the first of three Pre-Service-Issue Trials. They tested five carbines pulled at random from Inland’s first production carbines.  These carbines had modifications based on a previous test of pre-production carbines.  The conclusion and recommendations of the first pre-service tests had the following:

“The new slides could not be made to function in any of the carbines. The bolt would not open far enough to feed the next round. The dimensions and weights were checked and the outside of the camming surface no differences could be found.”

(Bold emphasis added, no mention of the bolt camming area.)

The second test was performed on June 17, 19, and 22, 1942. From the report of the testing:

“During the initial test .. it was discovered that an unused (modified) slide would not allow the carbine to function semi-automatically if the carbine had been fired appreciably. A plausible explanation of this is the new slide’s bearing surface is comparatively rough and until broken in the used gun (with its gas port partially closed) does not have the power for operation.

The purpose of this test is to determine if the above explanation is the correct one or whether the modification of the camming surface is the cause”

(Bold emphasis added, clearly work was being done on the bolt camming area.)

In this test they used 4 of the 5 carbines from the first test as well as 3 additional Inland carbines. These new carbines to the test carbines had modified slides. One of these added carbines was Inland 269.  They also brought in 5 unused old type slides and 6 unused modified slides to test.

The results of the test showed the modified slides showed no unusual number or type of malfunctioning. Both the unused modified and old type slides allowed the carbine to function reasonably well. However, in the rain tests, the modified slides showed more difficulty in closing the bolt when charging the piece, than those with the old type of slide.

What is interesting is how the cam shape is that of the M1 Garand.

We have no reference to what was old, new, modified, or which one of these was used in production. What was new yesterday could be old the following day.

Whatever this unusual slide is, it is not what we know from early production. It could be possibly carried over from pre-production, or it could be one of the slides used in testing. Either way, it is very interesting!

We ask the membership to check their early Inland slides and trigger housings and report if you have seen any of these early or unusual parts.

For further reading see:

Parts Development Trials: War Baby! Pages 84 to 92, War Baby III pgs 940, 1058

Ammunition: CCNL 104, War Baby! pg 88, War Baby 2 pg 678

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