Probably one of the South African kits they used on the last build, receivers were said to be cast by either Ruger or Caspian, Century never revealed their source. This batch had a minor issue, the face of the reciever cut a couple hundreths of an inch to deep, just trim said amount off the gas piston to home fix, which Century actually addressed, but were not as bad as the Hesse recievered, or the run of Century's first attempt at their own reciever, unibrow feed ramps, bad, very bad. I've torn down and rebuilt on of these S.A. rifles, thing ran as reliable as an AK when I was finished.
Or it could have been a home build, FALs are one of the most popular for this, and alot of fun to tinker with.
The fire control group wasn't modified, trigger, sear, and hammer are not in a pack like the CETME, or the G-3, they are all new U.S. made parts for 922r compliance. However, the reciever is not made with the cut, nor can it be ever cut, the dimensions are very different, for the full auto sear, which is the component that makes the rifle full auto, and uses a semi auto only ejector block, also idfferent dimensionaly, and impossible to fit a full auto model in it's place. The selector switch will go to the full auto position, but, it will lock the trigger like as if it is in the "safe" position, as there is no safety sear to engage.
Standard barrel inch pattern rifles were made semi auto only, only the heavy barrel, and the mythical Aussie "b**** gun", standard barrel model, no handguards, no muzzle attachment, 40mm grenade launcher under the barrel, and a 30 round HB version mag) were full auto.
What was the price, if it's under $500, grab it, they are great rifles, one of the best MBRs ever made.
Shop was asking $1700 I believe. Supposely the 'A' position functions instead of locking the trigger as you mention. Owner said it felt like an auto trigger. What ever that is? BATF took the gun and held on to it for well over 90 days before finally returning it.
Asking $1700, that's way, way too much for a franken FAL, more than three times it's worth.
There is no way to feel if the rifle is full auto by pulling the trigger, if the BATF returned it, then it's a legal semi auto, no sear cut or full auto ejector block in the upper reciever. Some of those safeties did allow the trigger to function, mine didn't, but, the trigger pull is said to be stiff, gritty, and hard, but only semi auto. Most guys who have rifles with these lowers replaced the safety selector with a DSA made inch pattern style, due to design, does not move to the full position, and keeps the ignorant types from giving them trouble.
Awesome rifles. I have a custom built heavy barrel with a older Fabrica de Militar receiver and lots of elbow grease fitting other new surplus parts kits. In parts i have under $1000 in mine but it worth FAR more now.