I can't find anything to support your claim about weapons. Seems pretty much all online arms dealers I can find selling anything from grenades, machine guns, and even rocket launchers take credit cards and I'm fairly certain stores also accept them too.
> grenades, machine guns, and even rocket launchers
Umm, yeah - what country are you buying live grenadesor working rocket launcher online with a Mastercard? Cuz it’s not the US or Canada. And if it’s not a live grenade or working rocket launcher, it’s no different than any hunk of metal.
uh. yeah... us and canada are a tiny fraction of the world, also what is really buying using visa or mastercard? if i use visa to byy crypto and then get explosives (which can be transparently done) there is nothing they can or will do about it... - buying things online has nothing to do with countries or borders, nor is it always clear, to payment providers or even customers, what kind of scheme enables a payment..
I am not sure what the current state of the issue is, but there was an initial effort to restrict gun sales in various devious and deceptive ways since it is illegal to overtly do so because it is legal trade and economic activity.
I would not be surprised though if the clear illegality of the violation of the Constitution of such efforts were brought to the attention of the payment processors, and they were reminded that they would severely regret hastening attention on an effort that still needs to happen, a public electronic payment processing capacity.