it is ten correct?

It's either 10 U.S. parts or no more than 10 imported parts.  I can't remeber which.  What a really dumb law.

ETA:  You can't use 10 or more of the imported parts on the list.


27 CFR section 178.39

    (a) No person shall assemble a semiautomatic rifle, or any
    shotgun, using more than 10 of the imported parts listed in
    paragraph (c) of this section if the assembled firearm is
    prohibited from importation under section 925(d)(3) as not
    being particularly suitable for or readily adaptable to
    sporting purposes.