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Sniperscope: MWO 5-9342-1

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    Posted: Oct 08 2017 at 11:15am
November 2017-E

MWO 5-9342-1

Modification Work Order

Modification of Sniperscope, Set No. 1, 20,000 Volts,

Adapted to M2 Carbine

6 March 1957

Background: The Modification Work Order

A Modification Work Order (MWO) is a printed order directing that a certain part or assembly already received and accepted by the U.S. Army be altered or upgraded. Often the item(s) to be modified were already in service. Unlike manuals the MWO's were limited distribution items as they were only sent to the maintenance personnel of the particular units that serviced the equipment to be modified.

The modifications in an MWO may have already been implemented at the manufacturer. They are not an indication of when the modification or change was initially implemented other than it was sometime prior to the issuance of the MWO. Sometimes years prior. 

Modifications were dependent on the availability of the parts and tools necessary to make the modifications. Sometimes a MWO included a number of modifications. If a particular part was not critical and out of stock or unavailable at the time the work was done the modifications that could be completed were carried out.


The language of the Corps of Engineers can be a bit confusing. What follows is an attempt to interpret the instructions in MWO 5-9342-1 so they make sense to the rest of us. The information below consolidates the information spread out in the two pages of text instructions in the MWO. 

At the top of this page you can download and print the MWO to follow along. Note the copy attached was absent page 3 which contains figure 1. The missing diagram would be helpful with understanding the narrative that precedes it for the work to be done. If anyone has a better quality copy of the MWO or the missing page we ask that you share it with the club.

We have recreated what we think figure 1 was to help explain items in the MWO.

Paragraph 2 "New Parts Required"

Item 1. Eye shield assembly.  Engineer part No. D8247-18. (To be requisitioned only as needed.)

Discarded when replaced.

Instructions: Remove the old style eye shield assembly when itbecomes defective, and 

becomes defective, and replace it with a new eye shield assembly

Comment: Anyone know what the difference was?

Item 2. Grip switch bracket.  Engineer part No. D8247-119.

Item 3. Modified switch, grip assembly. Engineer part No. D8247-41.

Instructions: Attach a grip switch bracket assembly (item 2) to the carbine (fig. 3). Fasten a modified grip switch (item 3) to the bracket assembly. The present handle assembly can be modified by drilling two holes in the handle as shown in figure 3, using a number 19 drill to clear threads.

Comment: The switch/grip assembly was previously mounted with screws through the inside of the stock(not shown). The grip switch bracket eliminated this. The grip panels used short bolts at the top-front (number 1 in the below pictures) and two small screws (number 2, one on each side) at the top-rear to secure the grip panels to the metal.


Brackets having two sets of holes for adjusting the bracket to accommodate both M1/M2 stocks and M2 potbelly stocks are not mentioned in this MWO, even though brackets were already being modified before this MWO was issued.

Item 4. Light source adjustment eccentric.  Engineer part No. 08247-28-3; wingnut part No. D8247-26-2

Instructions: Install adjusting eccentric (item 4, fig. 1)

Comment: The parts are the wingnut and lever that replaced the previous eccentric bolt to hold the light assembly in place and adjust the light elevation. It appears they modified original type cam bolts by the addition of a tab so the elevation could be adjusted without tools.

Item 5. Shielded Cable Grip.    Engineer part No. D9373-1 Old Cable Grip Discarded

Instructions: Remove the present type cable grip and replace with a shielded cable grip (item 5, fig 2) and cut off strain cable flush with outside of wrap.



Comment: the original cable ends must have been subject to stress which would cause poor connections. The solution was to add long cable ends which had more contact area to the cable sheathing. A bracket was installed in the stress cable screw hole. The longer connectors were secured in the new bracket. Pictured below shows the earlier connectors and strain cable


Item 6. Modified telescope mounting bar.   Engineer part No. D8247-8-5

Instructions: Remove the old style telescope mounting bar and replace it with a modified mounting bar (item 6, Figure 1). The old style mounting bar should be modified as shown in figure 4. The modified part should then be returned to stock.

Comment: to allow the ejected casing to clear the chamber

Item 7. Fiberglas cover.   Engineer part No. D8247-49-2

Instructions: Install a pair of Fiberglas covers (item 7) in the battery knapsack if not already installed.

Item 8. Spacer, aluminum.   Engineer part No. C3375-6; Filter, out of corrector lens and filter assembly, No. 775-871 Discarded

Instructions: Remove the filter and filter gasket from the corrector lens, and install the aluminum spacer (item 8, fig. 5) in place of the two components removed. See figure 5 for assembly drawing. Mark next to name plate with center punch to indicate when this action completed (TM 5- 9342A, paragraph 37b).


Comment: Behind the objective lens assembly in the front of the scope is the small lens assembly referred to as the corrector lens. The red filter is easily seen if present. The corrector lens assembly was disassembled, the red filter removed and replaced by the aluminum spacer.

If the work was done a punch mark was placed at or near the edge of the scope name plate. 

Item 9. Reticle housing assembly.   Engineer part No. D8247-19 (Modified) (includes #332 bulb). Indicates discarded in one paragraph. In another to be returned to Columbus for modification if practical.

Instructions: Remove reticle housing and replace with modified reticle housing (item 9, fig. 1). This click type changes strike of bullet 6 inches at 125 yards.

Comment: This was the change from the nut adjustment reticle to the dial reticle. This eliminated a need for a tool to make adjustments. So far only one or two nut adjustment reticles have been seen, both on low s/n scopes by American Optical.

Item 10. Cover, lamp socket.   part No. D8247-24-1; gasket: part No . D8247-24-4 cover

Instructions: Attach lamp socket cover. Remove old cover lamp socket and install new cover (item 10, fig. 1).

Comment: The replacement provided more clearance for the wire at the back of the lamp socket that connected to the BNC connector. The cap being replaced was approximately .146" deep and unmarked. The replacement was approximately .323" deep and marked 8247-24 or 8247-24-4.

Item 11. Fuse holder.   Engineer part No. D8247-53-5 and 6.919/B775-163 Twist lock type Discarded

Instructions: Remove the present twist type fuse holder and replace with the "coin slot " fuse holder.


Comment: The problem with the black twist type fuse holders was that they extended beyond the sides of the battery and prevented the batteries from fitting into the battery charging racks. The black fuse holders have not been observed on the power packs or the battery assemblies used by American Optical. They appear to have been standard on most if not all of the battery assemblies from Capehart-Farnsworth.

Item 12. Fusecartridge, 5 amp. 32 volt, 3AG, Ord. 142630. Old fuse Discarded

Instructions: Remove the 3 ampere fuse and replace with 5 ampere.

Comment: Power Pack fuses

Item 13. Screw, machine pan head, slot, 6-32 NC-2A x 3/8 long.

Instructions: If the knob is loose on the power pack switch stake with clear "glyptol" or replace the screw with a No. 6-32 x 3/8 inch screw (item 13) and stake with clear "glyptol". (Note: common misspelling of Glyptal, a varnish used as a sealant and/or insulator)

Template & Gimlet

Instructions: Items discarded

Battery Case Nuts

Instructions: Tighten as necessary and stake with "glyptol"

The Carbine Collectors Club Copyright¬© 2017

This article and/or it's images are the property of the author. They're not to be copied without prior written permission (Title 17, Chapter 5, Section 501(a) U.S. Code)

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Post Options Post Options   Thanks (0) Thanks(0)   Quote m1a1fan Quote  Post ReplyReply Direct Link To This Post Posted: Dec 10 2017 at 9:49am
Somehow missed this one the first go around. Another great article. Have no idea what most of it means, but it really is fascinating. Thanks to the writer(s).
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