Tapco, according to an employee, stands for The American Parts COmpany. Because its name is an acryonym, its name should be used in all capital letters.
Presently based in Kennesaw, GA, TAPCO has been one of the primary domestic producers of 922(r) compliance parts ever since 922(r) became an issue for Americans. Probably their best-known and successful replacement part is the G2 trigger set, which is probably the most widely-used AK-47 compliance parts set on the market.
For more information, visit Tapco's website.
-- SeanNewton - 03 Apr 2009