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Carbine of Interest Inland 270

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New2brass View Drop Down
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Dan Pinto, Photo Editor

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Post Options Post Options   Thanks (1) Thanks(1)   Quote New2brass Quote  Post ReplyReply Direct Link To This Post Posted: Oct 01 2021 at 3:47pm
More on the "early pinned" slide stop.
Ron Dalhamer sent me some pictures to share. This was observed at a gunshow on display. Ron attempted to purchase but it was not for sale.
http://www.uscarbinecal30.com/forum/uploads/2396/Inland15.png

Notice how the hole goes through
Here is the other side.
http://www.uscarbinecal30.com/forum/uploads/2396/SlideInland15.jpg
Below is the slide for Inland 270, notice how it does not have this hole



The slide Ron had attempted to purchase was from Inland number 15 which was one of the 20 toolroom carbines considered the true 'pilot' of the mass produced carbines, meaning they were made by the blueprints on production machinery.

Does anyone notice any other similarities?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote HammerGrunt Quote  Post ReplyReply Direct Link To This Post Posted: Oct 01 2021 at 4:24pm
Grainy picture but the inside top portion of 270's Slide Cam area looks alot like this 15's cam area :-)


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Post Options Post Options   Thanks (0) Thanks(0)   Quote HammerGrunt Quote  Post ReplyReply Direct Link To This Post Posted: Oct 01 2021 at 5:20pm
I took 270 back out to Bruce Dow this morning and asked him to specifically look at 270's very different Slide cam & Bolt lug combo. He admitted that he had totally missed this odd design when he looked at 270 a month ago when I first took it to him. He was mostly focused on the early type rear leaf sight that was reported by Dan in the article :-)

Upon close inspection and much sliding of the bolt's lug in the Slide cam track, Bruce was intrigued by what he saw and I took a video of what he thought about this particular Slide-Bolt Cam interface and I sent the video to both Dan Pinto and Marcus Rust to listen to. 

Here's my transcribed synopsis of what Bruce says in the video and I apologize for the redundancy of his thoughts but I'm trying to accurately transcribe both what Bruce said before and after I asked him to make the recording :-)

1. This Slide is not a different Slide design, but it a purposely modified/differently milled cam interface of the standard early Slide and Bolt.

2. It looks like this slide and bolt cam combo was built to purposely Test the problem Inland was experiencing with its early Extractors failing, which he said was due to the Higher Velocity Ammo which increased the Gas Pressure which Rotated the Bolt Faster which caused more Centrifugal Force which caused the early type Extractors to fail.

3. He said Inland had to very quickly figure out how to put more Stress on the Extractor in order to determine what was causing the Extractor to fail, and to try to determine where, when, and how it was failing in their current design at that time. He believes Inland engineers created this 270's Slide-Bolt design to specifically force a faster rotation in order to test the cause of the early type 1 Extractor and Plunger failure problem.

4. He believes they used this Slide-Bolt cam combo to prove that it was in fact the new Ammo's increased velocity, increased gas pressure, faster rotating bolt, increased centrifugal force that was causing the Extractor failure issue. From this testing, he believes Inland engineers were able to determine that a new modified Extractor design was needed to eradicate the failures being produced by the increased velocity Ammo.

AND after a much closer inspection and reflection, Bruce now concurs with many others that this 270 most likely would not have been issued out to the Army for Combat use in this "modified slide bolt cam interface design" and due to its still retaining its Type 1 Extractor with its Type 1 Plunger configuration. He agrees that its more likely 270 stayed in house at Inland as a Test Rifle. He also looked closely at the unmarked type 3 Hammer and said it may well be a prototype Type 3 Hammer that was used by Inland for testing, and believes that is why there may be such significant Type 1 and Type 3 Hammer strike indentions on the non-Ordnance Bomb proof marked, but "P" marked Trigger Housing wall.

The INTRIGUE of this 270 Inland only continues to grow :-)


Edited by HammerGrunt - Oct 01 2021 at 5:48pm
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HammerGrunt View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote HammerGrunt Quote  Post ReplyReply Direct Link To This Post Posted: Oct 25 2021 at 11:52am
The more I learn about M1 Carbines testing and early production the more I realize why so many experienced / knowledgeable Carbine enthusiast are really interested in this Inland 270... 

I hope more of the Club's Members will see this Post because there may be others who have a few more pearls of wisdom out there to share on this very cool Carbine :-)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jackp1028 Quote  Post ReplyReply Direct Link To This Post Posted: Oct 25 2021 at 5:03pm
@Dan, aside from the difference in the slide stop, I noticed that there are other significant differences between 270's slide and the slide in the picture provided by Ron Dalhamer. The 270 slide has a perpendicular surface on the right side whereas the one shown in Ron's picture is angular, thus possibly affecting the rate of bolt closure. Also, it appears that the width of the top of the cam cut is greater in Ron's picture compared to the 270 slide. Notice how thin the section is at the top left of the 15 slide (maybe 1/16") versus the 270 slide (~1/8") or about the same as a standard Type 1 slide. This could retard the bolt opening timing compared to the 270 slide. These slides look totally different to me.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote HammerGrunt Quote  Post ReplyReply Direct Link To This Post Posted: Oct 27 2021 at 9:45pm
I think Dan was trying to show the inside top of part the cam on the slide has a similar wider milled out area than the standard production slide.
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Dan Pinto, Photo Editor

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Post Options Post Options   Thanks (0) Thanks(0)   Quote New2brass Quote  Post ReplyReply Direct Link To This Post Posted: Oct 28 2021 at 11:36am
Inland serial numbers 11-99 were Engineering Models. More specifically serial numbers 11-30 were Engineering Specials. These were not true production models that required considerable hand fitting.
These were made to prove the blueprints as well as helping shake down the machining setup and jigs.

If you take a good look at any slide you will see the bolt cam area is quite complex as the cut is done while rotating the slide to give it a helix curve for the bolt.
The 2 slides in question are very different manufacturing wise but clearly have similarities.

I bring up the Inland 15 slide because there is a possible perpetuated myth of early slides having the stop retaining pin. This possible perpetuated myth falls in the hands of ordnance/ Raritan Arsenal or whomever was laying out the manuals as they show slides like the one on Inland 15 as the "old style" in the FM

http://www.uscarbinecal30.com/forum/uploads/10/slide_pin.jpg

The slide on 270 is not what we see in production. It may have been first production or first production modified based on the ordnance documents on the slide testing.

The angles of the pictures can skew what we are seeing and make things seem as they are not.
The cam area picture of #15 was taken with the camera slanted and the box of the cam was closer to the camera than the cam. The slide is only a few degrees of rotation off the table.
The picture provided by Hammer  was taken more square to the slide but is rotated about 80 degrees more than the #15 slide.

here is a picture of the cam area on #15 that was taken more parallel. The cam area on the left looks a little wider than the picture in my previous post, It may be thinner than #270

http://www.uscarbinecal30.com/forum/uploads/2396/Slide_Inland_15_cam.jpg


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