TM 9-1275, TRIGGER HOUSING GROUP

Section 6

Paragraphs 24-27

TRIGGER HOUSING GROUP

24. Disassembly (fig. 61)

Disassemble the trigger housing group in accordance with FM 23-5.

25. Inspection

a. GENERAL. Inspect all parts for damage, wear, burrs, rust, foreign matter in recesses, deformation, and free action with mating parts. Additional inspection procedure is presented in the following paragraphs:

b. HAMMER. Check the nose of the hammer for wear or chipping. (See fig. 62) Chips indicate excessive hardness and warrant replacement of hammer. Check sear and trigger notches for wear.

c. SAFETY. The safety is subjected to little wear and therefore fails mainly as a result of breakage. Breaks usually occur at the points indicated in figure 63. Either the type of early manufacture or of present manufacture is satisfactory for use.

d. TRIGGER ASSEMBLY. Inspect the trigger for wear on hammer-engaging notches indicated in figure 64. Also check for broken edge in front of the hole as indicated.

c. HAMMER SPRING HOUSING. The hammer spring housing usually fails as a result of breakage. Inspect for cracks at the point indicated in figure 65. This is a visual inspection only.

26. Maintenance and Repair

a. TRIGGER GUARD.

(1) Excessive force is sometimes required to close the trigger guard on the rifle. (See fig. 61) This is usually true where the climate is humid and is the result of an increased moisture content which makes the stock swell. When this condition is encountered, correct by removing very fine shavings of wood from the underside of the stock along the bearing surface of the trigger group with a fine file until the proper fit is obtained. This surface is at a 10º angle to the horizontal. Use extreme care to maintain the 10º angle and to remove the same amount of wood from both sides of the stock. As wood is removed, determine the force required to lock the trigger guard by frequent reassembly. The normal force required to close the trigger guard is reasonable but not excessive. The trigger guard must not be loose as this is the only point at which the action is locked in its bedding. Make certain the guard latches properly.

(2) When the bow in the trigger guard is bent up to interfere with the tip of the trigger, it can be straightened or the tip of the trigger ground off. When the trigger guard locking lugs become worn, peen lightly (fig. 66) to resize them and then dress to shape with a fine file. The trigger guard fork may become sprung in, thus causing binding, or sprung out, thus preventing the hammer pin from extending far enough through for proper bearing. Correct these faults by springing the fork back into correct position.

b. TRIGGER HOUSING. Modify the pads on the upper rear corner of the trigger housing of early manufacture to the dimensions of present manufacture, as shown in figure 67. This is required to enable assembly of current design safeties.

c. CORRECTING TRIGGER PULL.

(1) Trigger pull too light. This is evidence of worn lugs on the trigger, worn lugs on the hammer, or a weak hammer spring. Examine the components for wear and replace with new components.

(2) Trigger pull excessive. This is caused by burrs on the lugs of the trigger, burrs on the lugs of the hammer that engage the lugs on the trigger, a hammer spring that is too heavy, an obstruction or foreign material in the hammer spring housing that prevents proper seating of the hammer spring, or a bent trigger that rubs against the trigger housing. Examine the parts for defects, remove all burrs, with a fine sharpening stone, and replace defective parts.

(3) Creep in trigger. Slightly rough contacting surfaces of the trigger lug may cause "creep" in the trigger, and are to be removed with a fine sharpening stone. Stone to a polish only, being careful to maintain proper level and angle.

d. BENT SAFETY. When the safety is bent so that it binds in the trigger guard cut, it is to be replaced. It cannot be straightened because it is hardened steel.

27. Assembly

a. GENERAL. Assemble the trigger housing group in accordance with FM 23-5.

b. INSTALLING TRIGGER PIN. When assembling a large quantity of trigger housing assemblies, use the assembling fixture to speed up work. This fixture is improvised and is to be made locally. (See fig. 17.) To seat the trigger pin head, place the trigger housing, open side up in the fixture, and engage the lug between the sear and trigger (fig. 68); compress hammer spring, align holes, and install trigger pin.

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