The post you said made no apparent sense.
I hope one of those actually solves your problem:
*Get a turret vehicle, like AA Turret.
*Make a 4x4 plate and play around with onPlayerTouch > Player > spawnProjectile > 100 [projectile] and if you have VCE, even better.
However, we can't do a in-detail reply since the OP Post is hard to understand.