Cash purchases are already pretty common for gun sales. All gun retailers accept cash, obviously, and many of the smaller ones offer discounts for purchasing with cash (usually framed as an extra 3% or so fee for purchasing with a credit card). The tinfoil-hat crowd is also fond of purchasing with cash, and many person-to-person gun sales are done on either a cash basis or as a miscategorized PayPal transfer.
Well firstly let's not disregard a proposal that could greatly diminish bad gun sales simply because it doesn't eliminate them completely.
This mechanism is more than just stopping an individual sale. If a store sells a certain class of products, they won't be able to accept credit cards at all. As you say, plenty of people will be able to just go get cash out, but how many people will just go down to the store down the road which will accept Amex? 5%? 10%? 30%?
How many stores can afford to lose that business to their competitors?
The result is that you'll likely end up with all large gun stores not stocking these items. You'll have a few boutique stores that can't take card, but do have a wide selection of more powerful weapons and then they can explain when 99% of school shooters get their guns from these 1-2% of gun shops.
> How many stores can afford to lose that business to their competitors?
I'm confident that dropping credit cards would result in less business lost than dropping standard-capacity magazines.
> The result is that you'll likely end up with all large gun stores not stocking these items.
Can you name some "large gun stores"? I know of a couple online, but I also know that the sets "customer who buy 'assault weapons'" and "customers who buy from large retailers" are very nearly disjoint.
> You'll have a few boutique stores that can't take card, but do have a wide selection of more powerful weapons and then they can explain when 99% of school shooters get their guns from these 1-2% of gun shops.
There are already at least ten million AR variants in the US. They don't expire.
