Not to seem paranoid, but I saw this awhile ago and couldn't help but think that a guy who does not appear to speak English as their first language wants ammunition for machineguns that are common in former Soviet and some third world nations (some with large Islamic populations), are rare in the USA, and if properly registered in the US would be rather expensive. However picked up in a third world market are probably some of the least expensive reliable heavy machineguns out there. Shopping in Somalia or Yemen you could get a great deal...
How many people that speak limited English reside in the US and have multiple expensive legally registered NFA firearms comparable to say an M2? (With the 14.5MM being almost twice as powerful as the .50 BMG.)
Most people that speak limited English in the US are not in the income bracket that can afford such things.
You are not a foreign terrorist planning to smuggle in some heavy machineguns without all the bulky and heavy ammo of such calibers and want to know where to buy the nearest ammo to feed them once they arrive are you?