The Mossberg 590 shotgun is the perfect alternative to the Mossberg 500. For one thing, the Mossberg 500 requires you to change the barrel before you can add a magazine extension to it. The Mossberg 590 does not require you to change the barrel in order to add a magazine extension, which is why a lot of people are choosing the Mossberg 590 now. If you are someone who shoots competitively or even in dangerous combat situations, you’ll want to have more ammo. The Mossberg 590 is the weapon you should choose in that case.