Smith Enterprise, Inc. built a "few more than 176" NFA transferrable select fire M-14 rifles before May 1986. These were billet machined receivers. Springfield Armory, Inc. made 125 NFA transferrable select fire M1A rifles before May 1986 wth investment cast receivers. These ~ 301 rifles are the only factory built commercial manufacture select fire M14 type rifles ever made. The select fire Chinese M14 rifles were made by a government owned facility, State Arsenal 356, Kunming, Yunnan, People's Republic of China. The same goes for the T57 rifle, those were produced at the 60th Arsenal, Kaoshiung, Taiwan.
For clarity, there's a difference between a select fire conversion and a reweld. In a select fire conversion, an intact semi-automatic receiver is altered after it has left the factory. Rock Island Armory, no longer in business but also owned by the Reese family, made thirty-five select fire M1A conversions before May 1986. There have been other BATF approved commercial M14 conversions performed by Hard Times Armory, R.P.B. Industries, Earl Banta, Charles Erb, Pearl Manufacutring, and Neal Smith. In the case of the M14, the operating rod rail is modified and a selector lug is added to the receiver. The select fire parts (selector shaft, switch, spring, pin and connector assembly) are then installed. As a bit of trivia, a Springfield Armory, Inc. M1A connector assembly is different than a USGI M14 connector assembly. That is because the forward underside groove on the operating rod rail of the select fire M1A is 0.030 " narrower than the USGI drawing 7790189 dimension.
A reweld refers to welding two receiver halves back together to form a firearm. For the M14, rewelds were usually done on cut USGI M14 receiver halves. Both semi-automatic (Hahn Machine and Co. and Pearl Manufacturing) and select fire (Bill Fleming, H&R Gun Co., John Norrell Arms, Inc., Neal Smith, Specialty Arms Co., and Metro Tech, Ltd.) firearms were created legally by rewelding receivers in the past. Do not do this now, it's illegal.
Based on what I've seen in the Class 3 ads over the years, a commercial manufacture select fire M14/M1A brings about the same amount as a rewelded select fire USGI M14. The ball park range over the last three or four years is $10,000 to $15,000. $12,000 seems to be a typical selling price. I haven't seen much of a price difference between a factory built select fire M14/M1A (Smith Enterprise or Springfield Armory, Inc.) or a select fire conversion of a commercial M14/M1A. FWIW and YMMV
