In a nutshell,
On July 6, 1989 the Secretary of the Treasury used the authority delegated to him by Congress under Title 18 USC § 925(d)(3) to restrict the import of “non-sporting” firearms.
On July 6, 1989 various military style semiautomatic rifles were determined by ATF to be “non-sporting” based on a variety of features and banned from importation. The authority to impose this ban stemmed from the 1968 Gun Control Act, specifically Title 18 USC § 925(d)(3).
Shortly thereafter, various manufacturers began importing foreign parts and assembling them on locally made receivers. Congress responded in 1990 by passing new regulations. Title 18 USC § 922(r) made it illegal to build any firearm prohibited from importation as “non-sporting” under Title 18 USC § 925(d)(3). Note that only assembly is illegal—possession, transfer, etc, of such a firearm are not covered.
However, the 1990 law was so vague that in 1993 the ATF wrote regulations (178.39) that spell out the “10-or-less imported parts rule” and what “imported parts” mean. It states that only 10 imported parts are allowed in an unsporting imported firearm. This new law and regulation shows up in the 1995 Federal Firearms Guide. During the interim many rifles were built at home from imported parts without concern to parts count.
Any foreign semiauto rifle assembly or modification since the import law took effect requires that compliance is met. Currently making a MAK90 into a non-importable pre1990 configuration (regular pistol grip AK) requires that compliance parts are swapped in making the MAK90 exempt. Best to use parts that say made in USA. Tapco has such parts.
http://www.tapco.com/product_list.asp?dept=15&last=39
Lummox didnt mean to imply tha your encouraging a felony. Just seemed like keeping it legit wasnt a priority. Glad you know better.