Is the hold up is due to shipping you the parts, here are the firearms shipping rules for USPS, UPS & FedEx. USPS has a exception for LE.
http://www.cgwgun.com/shipping/usps.aspxhttp://ups.org/content/us/en/resources/ship/packaging/guidelines/firearms.htmlhttp://fedex.com/us/services/terms/(F3) May a dealer sell firearms to
law enforcement agencies and individual
officers in another State?
Yes. Sales and deliveries of firearms
to out-of-State police and sheriff
GCA. A dealer may also sell or ship
firearms, other than NFA firearms, to
an individual law enforcement officer,
regardless of age, if the dealer has a
signed statement from the officer's
agency, stating that the items are to
be used in the buyer's official duties
and that the officer has not been convicted
of a misdemeanor crime of
domestic violence. No ATF Form
4473 or NICS check is required; however,
the bound book must be properly
posted, and the signed statement
included in the dealer's records. For
further information on sales of firearms
to law enforcement officers, see
Item 4, “Sales to Law Enforcement
Officers”, in the General Information
section of this publication. You should
contact your State’s Attorney General’s
Office to ensure there is no
State prohibition on such sales.
[18 U.S.C. 925(a) (1), 27 CFR 478.134 and
478.141]
departments are not prohibited by the