Are you telling us that Armscor accepts illegally shipped firearms? I seriously doubt that. Either you are not telling the truth or you'll soon have some legal troubles.
Nothing illegal about it, and it's been discussed ad nauseum on gun forums.
Fedex isn't the USPS, and it's only company policy to require firearms be shipped next day. "Machine parts" don't have the same requirement for next-day shipping.
Please do me the courtesy of telling me which law is being broken. Below is a link to US Code governing the shipment of firearms. Thanks.
18 USC § 922 - Unlawful acts: