This is the advice you'll find in every forum thread: skip Shopify Payments, bolt on an Authorize.Net gateway, sell away. It solves exactly one of the three documents above. The gateway swap gets you out of the Payments prohibited-business list — and leaves you fully exposed to the platform product rules, which is where enforcement actually happens.
Industry reporting suggests Shopify Plus reviews some firearm-adjacent and ammunition merchants case by case at the enterprise tier. That is a negotiated exception with an account team, not a policy a standard-plan gun store can stand on. For everyone else, the workaround holds right up until a policy sweep, a payment escalation, or a complaint puts human eyes on the catalog.
And when that happens, the failure is total: Shopify is your storefront, your hosting, your checkout, and your product database. Delisted products are the gentle version. The common version is a suspended store and a scramble to rebuild somewhere else while your ad spend and SEO bleed out.