Halio

I don't know if this is my own problem. Because I saw couple of video in internet which works flawlessly. At first the gun was not apeared in part list. Then i checked part.cfg and found "category = 0", after it is changed into "category = Science", i am now able to set up the gun and fire it. The problem is that it causes huge lag every time I shoot, after kept pressing the fire key, game will just crush. Does anyone experience the same as me?