4 Year Old Boy Obsessed with Guns

My 4 year old son is currently in 4K.  He is constantly getting in trouble for pretending to shoot guns and talking about killing.  He loves to play all games associated with bad guys and good guys such as cowboys and indians, star wars, and all super heroes.  When he plays these games, he usually pretends he has a gun and the bad guy gets killed.  At home, he has not been allowed to have guns or watch any tv shows or movies about super heroes, star wars, etc.  His school has a zero tolerance policy for talking about guns, so he is always in trouble.  He is not controlling his impulses well at all and will get in trouble right after he has just been disciplined.  At home, we had tolerated him playing good guys/bad guys, but have now stopped because he doesn't seem able to draw the line between home and school.  We use time outs at home and also had him put in a bag last night all of his toys that he got for Christmas that could be associated with guns such as star wars, spiderman, etc.  He eats a well rounded diet and sleeps well.  He also has difficulty though with having bm's in public.  He does not ever want to stop playing to go to the bathroom and will instead have accidents in his pants.   This has caused some behavior problems in the past as well as he gets rather fidgety when he is withholding bms.  My husband and I don't know what to do anymore.  He has been having behavior problems ever since he started 4K.  I'm just not sure if this is typical 4 year old boy behavior or something more.  I want to resolve these problems before he starts 5K, but am not sure how to change these behaviors.  ANy advice would be appreciated.  Thank you!

[margypops]

so who did he learn this behavior from? is he allowed to watch movies with killing in, does his Dad like these kind of ,movies or DVDs this kind of behavior is nearly always copied and learned behavior he wont stop it till who ver taught it to him does..

[91004]

Most kids play cowboys and indians(my son learned that from tweetsie railroad which is for families)  I wouldnt of taken his toys from him. If it started when he started school then that is probally the problem he is having trouble adjusting.  Try playing school with him at home let him be the teacher and you the student, then switch show him ways to behave in school. Give the toys back that you made him bag up and let him play he is a kid when he acts out at school then you take his favorite toy for the or dont let him play good guy bad guy for the day.