How do i shoot through a CanCollide = true?

how can i have a gun shoot through a CanCollide = true block

A couple methods:

1. CanCollide = true will block things like BodyVelocity, but won't block you animating the projectile with CFrame (advancing the position as frequently as possible). Of course, if you're using BodyVelocity, you can just set the projectile's CanCollide to false.
2. Set the block you want the projectile to get through on a different CollisionGroupId (see SetPartCollisionGroup). Put the projectile on a different collision group and then configure them so that they don't collide using the PhysicsService.