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1/6th scale M27 Recoilless rifle
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Pennsylvania, United States
Joined: March 12, 2008
KitMaker: 464 posts
Armorama: 371 posts
Posted: Sunday, November 11, 2018 - 06:45 PM UTC
Hi everyone, shortly after I finished off the M40 RR family I decided to take what I learned on creating those models / kits and put them towards creating the M40's predecessor, the M27.

I got the idea while I was doing research I stumbled across the M27 RR, but this variant was mounted on a wheeled trailer. In the past the only time I saw this system was when mounted to a M38, or M38A1 jeep. With the Trailer this makes the weapon more interesting for me as it now becomes a stand alone unit, similar to a anti tank gun.

To help with the model I was lucky to find the original tech manual for this unit online and once in hand I was able to incorporate many unique features that were present on the real unit on this model.

As for the model's construction media, like with the M40 I went with all 3D print. Parts like the Rubber tires and the optic eye cups are cast rubber made w/ printed masters

Also like with the M40 some parts which had small details were printed in the HD material, while the remainder was printed in standard. These HD parts would include the optics, Breech face, data plates... etc

One concept that I liked when designing the M40 was the idea of having as many parts on integrally printed as possible. By doing this I'm able to get very high levels of details w/o the need of having smaller sub assemblies or extra parts that end up adding to the kit's complexity and costs.

Once the model was started all the parts went together very quickly, and in no time I had the unit built and ready for painting.

One of the design features I took from the real unit was how most of the parts on the trailer are mounted. Parts like the tail, wheels, and even the M22 itself are all pinned on and no glues are used.

As for the M27 mounting it clips in place via two snaps, just like the real unit.

On the bottom portion of the tail is a travel lock that was also made to be functional

The model can be displayed in the firing mode, or in transport via a jeep / dodge / or Deuce.

Another feature that I built into the model was for there to be functional elevation, this was done similar to the real one where I have springs in the elevation tower, This allows the barrel to raise and lower, but prevents any sagging from occurring. In addition to the elevation full rotation is present too.

Like with the M40 I was able to get the data plate details made w/ full legible info. These are found on the M27's base and on the M22 trailer's body

Once fully painted all the fine details that are present on the base and other locations become more visible and noticeable,

Another cool feature that is found on the M27 is the dual optic system. For direct fire there is an M90C optic on a forward tower of the barrel, This tower also is where the trigger is found

For Indirect fire, a M79 optic was used. This would be mounted towards the rear of the receiver section. Because of this feature you have duplicate controls for the elevation

Because the trigger is up front, to connect the trigger to the sear, there is a long exposed steel cable w/ clevises that connect the two together. On the model real cable is used for this detail, and for the connections there are two small clevises as on the real unit

Just like with the M40 the Breech can open and close, and 3D printed rounds can fit into the chamber area... the only thing I was not able to scale down is the satisfying CLUNK that these breeches make when closed / locking in battery

After designing this one I can see why these were not in service for long as by the mid 1950's this design was already becoming antiquated. The M40 which replaced the M27 was a better design and is reflected in it's simpler layout and use of more modern materials, still makes for a cool build though.

And makes for an unusual piece to tow behind my Dragon jeep,

Since these were not used for a long period of time there are not as many variants developed compared to the M40, however there is another version on this trailer w/ smaller shorter tail, and one that is jeep mounted... which is defiantly something I'm looking into designing.

not to mention this bad boy which is not only in the tech manual, and I got a chance to see / play with in person

Until then though I posted more pics of this unit on the facebook page,

one thing is for certain the 1/6 AT gun bug bit me hard, More to come !

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North Carolina, United States
Joined: January 20, 2005
KitMaker: 916 posts
Armorama: 758 posts
Posted: Monday, November 12, 2018 - 11:04 AM UTC
Somebody is an Over Achiever ...

Seriously tho, that is quite impressive.
And making everything functional !

I assume you designed that at 1:1 and printed it at the 1:6 scale ?
So now you could print at any reasonable scale or would you need to rework it to get printable wall thickness ?
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Joined: December 30, 2011
KitMaker: 902 posts
Armorama: 788 posts
Posted: Monday, November 12, 2018 - 01:35 PM UTC
wow, is the word that comes too mind great job .
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Pennsylvania, United States
Joined: March 12, 2008
KitMaker: 464 posts
Armorama: 371 posts
Posted: Monday, November 12, 2018 - 05:52 PM UTC

Quoted Text

I assume you designed that at 1:1 and printed it at the 1:6 scale ?
So now you could print at any reasonable scale or would you need to rework it to get printable wall thickness ?

No actually when I make my scale drawings everything is already scaled down to 1/6 for thickness / clearances. From there I import my 2D files and build them into 3D. Also I have what materials I want to use in mind when I am designing.

Scaling things down from 1/6 to say 1/16 does cause some issues with part thicknesses. Sometimes this is fixable by a simple material switch as HD allows more precision compared to standard material. However some features like the data plates, or some of the functions would either have to be redesigned or deactivated for small scale production.