You didn't say what make of gun you had. Some of the exclusive deluxe boutique houses have recommendations on what brand of simple hardball to shoot in their guns. I once had problems with an early production Glock 19. Glock/GA fixed it but returned it with a huffy note that I should not use cheap foreign ammo (Norinco in those days.) but should stick to something like the WWB they tested guns with at the shop.