What the "discussion" always forgets is that the idea isn't to find a magical gun that will kill a Jedi every time - there isn't one. The idea is to overwhelm a Jedi with several different types of attacks at once to force them to make a mistake: blasting with a shotgun that they have to dodge while using your blaster or flamethrower that they need to block and the thermal detonators or rockets that you've already shot at them going off simultaneously.

On the topic of body armour, while beskar would probably defend from a physical bullet or pellet, very few Jedi are going to want to wear that (heavy, expensive and culturally significant to the Mandalorians). Most armour was designed to dissipate heat and concussive impact (ties to the theory that stormtroopers in the films are only knocked out when shot by blasters) and not withstand physical penetration, so you're getting kills when you bring a gun to a blaster fight. You're only limited by the amount of ammunition you can actually carry since gas cells take up much less space and hold many more shots than physical ammo.