Empire Airsoft, Kalamazoo Michigan.
I highly recommend sourcing parts/accessories from Empire Airsoft.
After my recent acquisition of a Systema M4 PTW, a few xtra accessories were required. Contacted Empire Airsoft in Kalamazoo Michigan, and via their website ordered a few items.
The Manager there, Steve is an awesome guy to deal with. He is very knowledgable and only too eager to help out in any way possible. Very informative emails and phone calls.
Packaging and shipping of the items was second to none. The package was here within a few days, sent by USPS/Canada Post NOT by UPS, and the shipping rates were very very reasonable.
Overall a very pleasurable experience, excellent people to deal with, and fast, secure shipping. 10 outta 10!!