Ok ,I will try to keep this as short as possible. I printed out and called in to the airport concerning the regs for carrying a handgun on Delta.Done everything to the T. Carried gun home.All worked flawlessly. Flew back to the same airport 5 days later without my gun. Landed in Detroit and we sat at end of runway for 40 minutes for no apparent reason. Then we pull into terminal, but stop short by @ 50 feet. Then several vehicals surround plane, which was getting a lil scary,then TSA officials along with US Marshalls and Homeland Security started to board plane as soon as door opened. I thought OH crap someone is in bad trouble and there may be a bomb or something on this plane and we need to get off of it.Well Really quick I was surrounded by 7 and escorted off 1st.I mean roughly too. They started by saying where is the gun? I was dumfounded and ascked what have I done and told them I had no gun on me , near me or in any luggage and all my guns were at home. I was forced to the ground after a half strip search and was being treated as a uni bomber or something. I was held at gunpoint by 3 while 20 or more was running all around, other people were escorted away and finnanly I was allowed to get up and walk up to a enclosed area while being drilled.I answered everything they asked but was mostly just detained while they found out my lifes history, info about my family, job, my high school and even my parents and probably the last time I used the jon.They tore my luggage apart( not literary but searched and even had a dog sniff it.) About a hour and 20 minutes of the worst day of my life had passed, then all of a sudden they said Ok, our computers threw a red flag up because you left here with a gun and didnt check one back in on return trip.Hell Im not sure F15 fighters didnt escort us in on landing????Were sorry for the mistake and your free to leave.I was shaken up pretty well, hate too fly anyway and we had a rough landing .Thats the best explanation I could get and got evil looks as I probed for a better explanation or more of an apology of some sort. Even have a few bruises on my upper arms from the death grips they had on me.It was no JOKE what had just happened.I had 3 ?s for the home security in charge , 1st, did I do everything right last week when I transported gun , answer was yes all good. 2nd ? How could I have actually made it on a plane with a gun, no answer.3rd, Why would they assume I would be traveling back with said gun? Answer , most who carry a gun , will return with one. I stumbled away and said if I knew the regulations the 1st time ,I would have done the same on return trip.I was so tore up I couldnt hardly find the truck in the parking lot.Still havent eat hardly anything all day. What a terrible expierience.After Ive thought about it, I cannot believe it all, and I cannot believe if they honestly thought and I believe they did, have a gun on board the plane , how could they have ever let us takeoff.Input?