Section I Assembly and Disassembly

1. GENERAL. The submachine gun will function correctly if it is kept clean and is properly oiled and maintained Thischapter explains disassembly, assembly, care and cleaning, stoppages and immediate action- It is a guide for mechanical training and outlines the procedures to be followed

2. NOMENCLATURE. Thenamesof the parts of the submachine gun (figure 1) should be learned during instruction in disassembly and assembly by referring to the illustrations and parts list. Generally, the parts are named for the job they do—I.e. the trigger guard actually guards the trigger from accidental or unintentional discharge. Adequate cleaning and oiling can be accomplished with the weapon broken down into the following groups: Receiver group. Barrel group, and Magazine. Some further disassembly of the magazine is required.

"Varies with brand of ammunition used

American 180 Parts Bolt

Figure 1 The American 180 disassembled. 1, Barrel Group — 2. Receiver Top Strap — 3. Bolt —4 Bolt Spring —5. Receiver Top Retainer Pin — 6. Receiver — 7 Trigger Group — 8 Stock — 9. Feed Block —10. Drum Magazine —11. Winding Mechanism

3. GUIDES TO FOLLOW IN DISASSEMBLY AND ASSEMBLY. These guides should be followed when disassembling and assembling the American 180:

a. Follow Ihe step-by-step explanation.

b. Do not attempt to disassemble or asse m bl e t h e weapo n ag ai n-st time.

c. II it is necessary to apply force, do it carefully so that none of the parts are damaged.

d. As the weapon is disassembled, line up the parts In the order of their removal. This procedure helps'ln assembly of the weapon, which is done in reverse order of disassembly.

4 PROCEDURE FOR DISASSEMBLY.

a Before disassembling Ihe American 180, make sure that the weapon is CLEAR. Pull back on the magazine catch (figure 2) and remove the magazine Inspect the teed block and chamber to ensure no ammunition is present In either. Allow the bolt to go forward by squeezingon the triggur. {Note: To pull back [retract) the boit, pull back ont he bolt handleto its rear-most position until it stops, then manually return it forward), b. Detachment of the rear stock is done by pushing in on detent

Homemade Stock TikkaAmerican 180 Magazine
Figure 3

on top of the stock near end ol receiver with your thumb, and simultaneously pulling off the stock (figure 3). c. Removal of barrel is done by loosening barrel locking screw, and removing the barrel by pressing barrel clip and drawing barrel away from the receiver.

d. Remove feed block by placing thumb and forefinger on either side of the feed block and pulling up away from receiver (figure 4).

e. Removal of cover is done by firmly holding the receiver with one hand . With the heel of the other hand, gently tap forward on the rear of the cover. Lift up

American 180 Bolt

Figure on the rear o[ Ihe cover while moving slightly forward (figure 5).

f. Remove the cover retaining pin from either side of the receiver (figure 6). g Remove Ihe boll by drawing back the bolt handle larenough to get one li nger on the f ace of the bolt; by pulling back and up with this finger the bolt will leave the receiver (figure 7) h. Removal of the trigger housing: depress the stop pin by inserting a steel punch into the hole and pressing (figure 8). Simultaneously, the trigger housing has to be drawn back and the sear positioned with the forefinger so that it does not interfere with the removal of the trigger housing (figure 9).

5. ASSEMBLING THE AMERICAN 180. Assembly is done in reverse order of disassembly

6 OPERATION CHECK. With the American 1 SOfully assembled and unloaded, and the safety rotated forward into firing position [figure 10) the following operation checks may be made:

a. Push the selector to the left. With the trigger released, pull the bolt handle sharply to the rear The bolt should be engaged and held by the sear, b Squeeze and maintain pressure on the trigger. With the trigger depressed, the bolt will go forward. Pull the bolt to the rear, the sear should again engage the bolt while the trigger Is depressed.

c. With the trigger released, pull the bolt handle to the rear, cocking the weapon. Push the selector to the right (automatic) position. The bolt should not move until the trigger is squeezed.

d. With the selector in the automatic position, pull the bolt handle to the rear: hold the trigger back. The bolt should move back and forth freely, not being engaged by the sear e Test the safety with the selector in both the semi-automatic and the automatic positions.

American 180

Figure 6

American 180

Figure 8

Figure 6

Figure 7

Figure 8

American 180
Figures
American 180
Figure 10

Section II: How the American 180 S.M.G. Functions

1. GENERAL

a. By disassembling and assembling the American 180 you should become familiar with the parts. The next step is to learn how these parts function. If the user understands how the American 160 works, he will be able to keep it in operating condition and reduce any stoppages which might ocCurduringfiring.This knowledge will give the user confidence in his weapon, b. Each time a cartridge is fired, the parts inside the American 180 function in a given order This is known as the cycle of operation.

c. The cycle of operation of small arms is broken down into eight basic steps However, in the American 180, two of these steps—locking and unlocking—do not occur. The six basic steps of the cycle of operation of the American 180 are listed below In the proper sequence, although more than one step may be occurring at the same time,

(1) Feeding—the placing of a cartridge In the feed block, in front of the bolt, so it can be chambered. This action takes place in the magazine generally, but can be accomplished manually.

(2) Chambering—moving the cartridge forward until it Is properly seated in the chamber.

(3) Firing—the striking of the primer of the cartridge by the firing pin to ignite the cartri dge.

(4) Extraction—removal of the empty cartridge case from the chamber.

(5) ejection—removal of the empty cartridge case from the receiver.

(6) Cocking—retraction of the bolt far enough so that it will pick up a new cartridge and, as it moves forward, will have enough energy to fire the new cartridge.

2. FUNCTION OFTHE AMERICAN 180. As the bolt is moved back to a cocked position, the driving spring is compressed, and the sear engages the sear notch of the bolt. When the trigger is pressed, the sear releases the bolt, which Is driven forward by the drive spring During this forward movement, the bolt pushes a cartridge from the feed block into the chamber. The bolt continues forward and fires the cartridge. When the car tridge is fired the chamber pressure forces the bullet out of the muzzle of the barrel. At the same time, this pressure overcomesthe forward movement of the bolt and starts it to the rear By the lime the bolt and empty cartridge case have moved to the rear far enough to open the rear end of the chamber. the bullet has left the barrel and the chamber pressure has decreased. (In thoAmerican 180, the chamber pressure is relatively low and the bolt is relatively heavy, thus eliminating the need for the steps of locking and unlocking,) During the rearward movement of the bolt, the empty cartridge case is extracted and ejected, the driving spring is compressed, and the next round In the magazine moves into the paws of the feed block. The rearward movement of the bolt is stopped by the compressed driving spring.

3. OPERATION OF THE TRIGGER AND SEAR.

a. When the trigger is pressed, it rotates around the trigger pin and forces the sear to rotate around the sear pin, causing the sear nose to be moved down and away from the sear notch in the bottom of the bolt. This allows the bolt to move forward under the action of the expanding drive spring.

b. Automatic tire—With the selector pushed to the right (automatic position), if the trigger is held to the rear, the nose of the sear cannot engage the sear notch of the bolt. The bolt will Continue to move forward and backward, firing the weapon automatically untit the trigger Is released.

c. Semi-automatic fire—With the selectorpushedtothe left (semiautomatic position), when the trigger is pulled, the nose of the sear disengages from the sear notch on the bottom of the bolt, allowing the bolt to move forward. At the same time under the action of the sear spring, the sear is moved back into position to engage the bolt and hold it to the rear until pressure is released from the trigger.

4. FEEDING.

a. When a loaded magazine is placed on the weapon, the magazine catch holds the magazine in position. The bottom cartridge is held by the feed pawsofthefeed block through the action of the magazine spring and follower. When the bolt moves forward, it removes the round from the feed block.

b. When the bolt moves to the rear and clears the feed block, the next cartridge is placed In the feed block by the action of the magazine spring and follower

5. CHAMBERING -The bolt, moving forward under the action of the expanding drive spring, pushes ihe cartridge out of the feed block. The bullet ramp of the feed block aids in aligning the cartridge with the chamber. As the bolt continues forward, the cartridge Is pushed into the chamber by the front of the bolt The base of the cartridge protrudes slightly from the chamber when the cartridge is fully seated.

6. FIRING. After the cartridge is chambered, the bolt continues to move forward- The extractor springs out under and snaps onto the rim of the cartridge. At the same time, the fixed firing pin sfrikestheprimerofthe cartridge, firing the cartridge. At the instant of firing the cartridge is enclosed in the chamber, and the rim of the cartridge is engaged by the extractor

7. EXTRACTION When the cartridge is fired, the gas pressure forces the bullet out of the muzzle and the empty cartridge case out of the chamber, pushing the bolt to the rear The extractor holds the base of the cartridge case against the bolt. The bolt continues moving to the rear, carrying the empty cartridge case with it. Extraction is completed when the front of the cartridge case clears the rear of the chambcr. If the cartridge is not fired, the extractor will remove it from the chamber when the bolt is manually pulled to the rear.

8. EJECTION As the bolt moves to the rear, the empty cart ridge case is held by the extractor. When the front of the cartridge case clears the rear of the chamber, with the extractor serving as a pivot point, the cartridge case is deflected out of the ejection opening in the bottom of the receiver.

9. COCKING

a. Semi-automatic—As the boit moves to the rear, the drive spring iscompressed, the nose of the sear will move up. As the bolt moves forward, the sear nose will engage in the sear notch and hold the bolt to the rear in a cocked position. The trigger must be released and pulled to fire again, b Automatic—If the trigger has not been released, the bolt will continue forward and the cycle ol operation will be repeated.

10. OPERATION OF SAFETY The American 180 has a positive safety that blocks the sear when rotated to the safe position.

22machine Gun Rifles
Figure 11
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