The drawings show the shape and give the dimensions for a Lightning Link that fits in the Colttm AR-15. If it's to fit in an after market lower receiver it may be necessary to change the outside dimensions. Either way. all that's really important is that it fits inside the receiver and can move back and forth about 1/16 inch.
When building the Lightning Link without a milling machine I find the simpliest way is to cut the long piece to length and width. Next center ^[Dunch and drill a l/B inch hole at each corner of the large oblong hole at one end. With a dremel tool and bonded cutoff wheel cut out the material between the four holes you drilled.
Next center punch and drill a l/B inch hole so you can cut out the .130 wide tail that extends out of the oblong you have already cut. NOTE Do not square off the end of the .130 cut at this time.
Center punch and drill a 1/32 inch hole at each end of the .043 slot at the other end of the part. Cut the slot out with the dremel tool and bonded cutoff wheel. Square the ends and finish the slot using a needle file.
Clean up the oblong hole and .130 wide cut with a small file. NOTE Now's the time to square the end of the .130 cut. CAREFUL Don't get carried away. The distance between the frcnt
[squared end) of the. 130 cut and the rear face of the .043 slot can not be any more than 2.120.
File cr grind the outside edges to shape until it fits into the lower receiver without touching the inner receiver wails.
To check the link for fit and function, drop it over the hook on the disconnector, refer to drawings [A) and (B). Hold the trigger back and cock the hammer. It will be caught by the disconnector hook. Now place a scribe or anything that will fit into the slot at the rear of the link and pull it toward the back of the receiver, the hammer should fall. If it did. keep holding the trigger, recock the hammer and do it all again. As long as you hold the trigger back, the link will release the hammer. When you release the trigger, the link can no longer release the hammer from the cocked position.
If the link would not move back far enough to pull the disconnector hook off the hammer, find out what's stopping it and correct the problem.
Assemble the parts. Refer to drawing [CL Install the parts in the lower receiver. See drawing (A). Tip the weapon so the link's upright rests against the rear of the receiver. Close the upper until the take-down pin post is far enough into the lower receiver, that when you tip the firearms muzzle down the link's upright can rest against the post. Continue closing the weapon until it's completely closed. NOTE This first time you may have trouble getting the link upright to slide in place between the rear of the take-down pin post and the bolt carrier. All I can tell you is wiggle and jiggle things until it goes in place. It will fit in place much easier after it's shaped by the bolt carrier.
After the take-down pin is in place, hold the trigger back and operate the bolt carrier about five times. The bend in the top of the links upright is formed at this time by the bolt carrier hitting it. See drawing CD]. Be sure to let the bolt slam with full force each time. Now's the time to find out if everything's working right. Cock the weapon, point it in a safe direction and pull the trigger. You should hear the hammer fail. Keep holding the trigger, cock the weapon, and release the trigger. Pull the trigger, nothing should happen, the lightening link will have released the hammer when the ; bolt carrier closed.
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