Give them (Clyde Armory) a call and ask about debt cards.
The issue is with the processing fees that banks charge for credit cards. Especially bad are the cards that offer cash back to the cardholder. That 2 or 3% you get back is deducted from what the merchant receives. Some American Express and Discover cards can cost the merchant 5 to 8% which on something expensive like a H&K gun could be $40 to $60 that the merchant looses.
I would call up www.policeguns.com for the gun. I would then mail them a certified check, as most likely a debit card will be considered a credit card for their card processing company, and send them a copy of an FFL you wish to use. Then I would pay my FFL once the gun arrives.
Afterwards I would send the gun to Tecumseh for making all of this possible.
A forum dedicated to and laser-focused on Heckler & Koch firearms, Heckler & Koch accessories and the owners and enthusiasts that love them! Come join the discussion regarding HK pistols, long arms, NFA arms, HK accessories, HK history and trivia and more.