FN FAL “Frankengun”

The Fusil Automatique Léger by Fabrique Nationale Herstal is a famed self-loading battle rifle made in over 90 countries in vast numbers and variations. At one time many were declared surplus and the receivers cut apart. American companies bought this "scrap", made receivers and other parts, and then assembled the semi-automatic rifles for the American market. These guns have been made with parts in various condition. They might be like new or worn out.

The phrase "tolerance stacking" takes on a whole new meaning with some of these rifles. Many manufacturers are out of business due to shoddy manufacturing, adding further to the range of quality. Some, of course, are top notch in quality. Recently one of these FN FAL "Frankenguns" was brought to me for repair. All I was told is it would not cycle. FAL rifles have a gas Take care to restrain other parts.

Given the range of tolerances of numerous parts, finding a plug that just happened to be larger and large enough to seal would be blind luck. Instead, I retrofitted the plug I had as shown. " Numerous makes creates numerous parts. Just the sort of thing leading to a mixed "Frankengun." system the can be adjusted as well as completely turned off. Owners commonly do not understand this and have it so far out of adjustment it will not cycle. In this case, testing revealed this was not the issue here.

Further investigation revealed the gas port was partially blocked. Clearing is was easy and there was no burr in the bore. The gas tube has two slots and must be pinned to stay open and in place once adjusted. Simply thread it in until the slots are wide open. The pin was missing in this case but these are quite simple to make and install. Use soft steel and dress it down flush with the tube. Despite the fix, testing found it still would not cycle.

The barrel on this rifle was well over the legal length, not even including the removable muzzle break. However, this was still shorter the original barrel. I opened the gas port to 0.121. Though further testing demonstrated this improved things, this was still not the full cure. From the start, I knew a lot of gas was leaking out of the gas plug. This was clear from the carbon visible around the plug. I had placed masking tape from the left side, around the front of the gas plug, and to the right side.

Firing one shot would blow the tape off the rifle, demonstrating the leak. Finding a plug that was over size

for a refit would be difficult at best as no parts supplier was going to measure them for me. Buying a box full of plugs in hopes of finding one that fit was out of the question. I did buy one and it helped a bit but was still not cycling fully. The solution was a sealing ring on the gas plug that would rest against the gas block. I used the sealing washer from a spark plug to make the seal. These washers are very soft and malleable.

First, make two cuts in the washer with side cutters and remove about a 1/8" section. Then, simply place it on a steel surface and tap many times with a hammer to thin the washer. I needed 0.020 and had it reshaped in a few minutes. Bend the washer to fit around the gas plug. When installing the plug it should be a very snug fit. In testing I did not need the gas fully on to get complete cycling. This made a satisfying and cheap fix for a "Frankengun." AG