Frank-en-gun: Noun, a firearm pieced together with parts from various sources in reference to the Frankenstein monster.
I’ve been in the process of redoing, re-furbishing, updating and upgrading some of the AR15s I built in the 1990s. Those were all pretty much standard rifles and carbines using carry handle receivers in either A1 or A2 configuration. Over the years barrels, upper and lower receivers, stocks and such have been moved around. The quest was to update some of those with more modern components such as new stocks, pistol grips, sights, optics and/or free float railed hand guards. In essence all of these are Frankenguns.
When all was said and done I realized I had a bunch of carbines but no full length AR rifle to shoot in CMP Service Rifle Matches. Looking around I then realized I had enough parts to put a rifle together.
Barrel: 20″ heavy barrel (shown on the top AR in the photo above) taken from an A1 upper I bought during the Clinton Assault Weapons Ban (AWB 1994-2004). Near the end of the ban people were dumping those post ban configured parts so I gobbled them up for future projects. The barrel had a 1:9 twist and a pinned on muzzle brake (flash hiders were banned). The barrel was very accurate but the muzzle break was obnoxiously loud. I had put it on the flat top upper in the above photo.
Upper Receiver: The upper receiver I chose to use was from a well used Colt M16 surplus rifle brought back from the Philippines as parts kits. Second AR from top. The guy originally hacksawed the barrel to remove the banned flash hider. As a result I bought it pretty cheap. I removed the barrel, had it recrowned and threaded for a flash hider and made a carbine out of it. You might recognize the lower receiver on this as being an original once piece long (stock, pistol grip and receiver) plastic receiver from Cavalry Arms. That stock was sold and replaced with their upgraded shorter model 2 stock.
Stock: The rifle stock and pistol grip shown on the top AR in the photo was originally on the AR on the bottom. That AR on the bottom was a pre ban Olympic “SGW stop sign” marked lower. That lower with the rifle stock was the first AR I ever built. As you can see I turned it into a carbine but eventually sold the stripped lower to a guy in the socialist republic of New York who needed it to build a pre ban gun.
Lower Receiver: The lower was taken from the third AR from the top. It is a Stag Arms lower. I bought 3 stripped receivers in the early 2000s and used them to build various ARs including a pistol. That one was taken from that carbine when I was redoing it into something else.
Miscellaneous Parts: Internal parts pretty much came from the donor rifles. That includes lower parts kits, hand guards, buffer and spring, front sight base. The pistol grip was a basic A2 from my parts box.
Assembly was pretty straight forward with a couple exceptions. The barrel originally had a pinned on muzzle compensator which was removed. I also had a scope on it at one time. To see through the scope I cut down the front sight base. At the time, low profile gas blocks weren’t available like they are now. To make it as original as possible I had to get the barrel threaded for a flash hider and replace the front sight base. I have a friend to did the barrel for me at no cost and I took the FSB from the old Colt upper (second AR from top).
End Result: Though well worn, a pretty nice full size rifle. The heavy barrel makes it very stable. With AR carbines being so popular, people tend to forget how nice a full size AR feels.