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Working on M3 setup, quest for parts and intro

Printed From: The Carbine Collector's Club
Category: The Club
Forum Name: Infrared Scopes and Equipment, Night Vision
Forum Description: Sniperscope, Snooperscope, Metascopes, T3 carbines
Printed Date: Feb 05 2023 at 5:49pm
Software Version: Web Wiz Forums 12.01 -

Topic: Working on M3 setup, quest for parts and intro
Posted By: FolkeM
Subject: Working on M3 setup, quest for parts and intro
Date Posted: Feb 14 2021 at 8:51am
Hi all! I am finally getting around to looking at my M3 setup. I seem to be almost complete, except for a couple of small items.
Maybe someone on this forum may have some spares or know of sources?
I am in need of a couple of screws for the Bakelite box on the left side of the scope, a nut for the mounting bracket and most importantly one of the cable couplings connecting the main cable to the switch. All shown in the photos. IF the upload is successful.
I live in Norway and collect mainly machineguns but also a few carbines and other items in my collection. I have written some books, mainly about German MG’s and other machineguns.

Posted By: FolkeM
Date Posted: Feb 14 2021 at 8:55am

hopefully pics will show

Posted By: sleeplessnashadow
Date Posted: Feb 14 2021 at 7:43pm
Greetings Norway,

If you can find a copy, recommend this manual for it's comprehensive list of parts. It's not perfect but it's the best the army published for the M3 scope parts.

TM 5-1090-202-25P

Organizational Field and Depot Maintenance Repair Parts and Special Tool Lists Sniperscope: Infrared FSN 1090-034-7788
Rack: battery charging with rectifiers;
for M2 and 20,000 volt sniperscope FSN 6130-377-0401

The box on the side of the scope missing the 2 screws is called the junction box. The screws are 6-32 thread, 3/8" in length. Each has a plastic washer 0.140" inside diameter, 0.265" outside diameter, 0.031" thick.

The screw at the front of the junction box also needs a compression spring that is a ground. It fits real tight to the threads of the screw.

The BNC connector for your cable is no longer made. Someone here may have an extra.

The nut that goes on top of the barrel clamp has a non standard thread. It also has a washer.

Times are a little difficult for a few people here who may have one or more of the parts you need. I'll ask one of them to have a look when he gets a chance.


Posted By: FolkeM
Date Posted: Feb 15 2021 at 4:53am
Jim, thank you for the detailed info.
Hopefully someone has the parts!

Posted By: New2brass
Date Posted: Feb 15 2021 at 12:17pm
Welcome to the forums.
the junction box screws are actually 7/8 long stainless steel with heads painted black" rel="nofollow -
do you have the spring?
The barrel mount requires a flat washer and two thin (.155)  1/4-28 nuts with an outside flat of 3/8 of an inch. As mentioned not a common item and the closest I can find is this which is 7/16 across the flats and slightly thicker" rel="nofollow -
the cable end is a BNC connector made by Amphenol number 74868 UG-88. They are no longer made in the black paint but can be found in a bright finish. The issue is going to be putting one on as you have to carefully trim the cable insulation to get to the braided wire. they tend to get brittle and if you score it then the fine wire will just break. all of this shortens the wire which is on the short side to begin with.
I will be following up later with an email on some other information.

-------------" rel="nofollow - Club Survey Saginaw Receivers

Posted By: FolkeM
Date Posted: Feb 15 2021 at 1:49pm
ok thanks for the input! All is appreciated.
Not sure if I have the spring for the junction box, where does it sit?

Posted By: New2brass
Date Posted: Feb 15 2021 at 2:55pm
the spring if present should be in the junction box in the front screw hole.

I forgot to add that the screws I linked for the junction box are longer than spec and you may need to grind them down a little bit. You also need plastic washers.

-------------" rel="nofollow - Club Survey Saginaw Receivers

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