Sear Open Bolt

Diagram 4139

THIS PART IS MADE TROM .125-INCH-THICKNESS, IEAT-TRCATAGLE STCCL. T SHOULD BE MADE SLIGHTLY OVERSIZE AND FITT£0 DURING ASSEMBLY.

PIVOT PIN HOi F IS .087" IN DIAMETER.

Homemade M16 Trigger Blueprints
.250"

TRIGGER DRAWBAR AND DISCONNECTOR

Diagram

Full automatic lire is achieved by pulling the Lrigger farther to the rear, against the pressure exerted by the U-shaped wire spring located at the rear of the trigger. This causes the forward end dI the trigger to contact a projection loeated on the lower end of the scar, which, if the I rigger is held back, holds the sear out of engagement with ihe holt. allowing it to move forward and back unimpeded. I'his causes full automatic lire.

The sear is cut from 5/8 (.625)-inch-thick steel plate. This must be of a type that is shock-resistant and capablc of heat treatment. As usual, 4140 or 4340 will serve admirably for this. Note thai ihe disconnector spring bears against the pivot pin. providing friction to hold it in place. The disconnector spring is .VI6 inch in diameter, wound from .018-inch wire, and the uncompressed length is between .300 and .400

inch, llic sear spring, local cd in the lower front side, can he a section cut from the Ml Carbine recoil spring used iti the closed-bolt version.

The trigger is made from the same material with a projection at the forward end on the right side tu engage the trigger bar/disconnector. I wo small 1/16-inch-diamctcr holes are drilled in the location shown to accept the U-shaped wire spring, which is formed from -065 inch music wire. I'his spring bears against the lower side of

Schematics Gun Homemade

the safety shaft, providing resistance to rearward movement of the trigger after the first, or semiautomatic, stage.

I he trigger bai should he made from similar material, except that it is only I/8 inch thick Ruth the hook at the bottom and the lump at the top should be left slightly oversize to allow fitting during assembly.

For use in the closed-bolt version, an original firing pin can hardly be improved on. Ht-re again, one can be purchased for less (ban the cost to make one. A drawing is included, however, in the event thai manufacture should be required. Drill rod will suffice as material for this. Stems from automobile engine valves or shock absorber shafts can also be used. The experienced lathe operator will know to use a sharp cutting tool, set exactly on « enter, taking light cuts. Those who have never done this before may gain some valuable, although unpleasant, experience when making a pait such as this.

.126"

.375"

INi-

2.00"

.100"

FIRING PIN

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  • Alison
    How do i make trigge for homemade shot gunr?
    7 years ago

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