“All manufacturers say this. It’s for liability only. “
Not true. It is because they have had years of experience with bad quality reloads that have damaged firearms returned for warranty work. I have personally spoken to two very large gun manufacturer CEOs who have backed that statement. They find reloads safe as any ammo when assembled correctly, it is just that reloads compared to factory ammo is radically different. Reloads account for nearly 100% of firearms damaged by defective ammunition so they strike reloads from the warranty.