hello I just wondering do I have too pay money to the gun companies to use there guns like counter strike

I think you should check with the companies.

It is a legal gray area but it is generally accepted that you would need to pay a license fee to use a real gun or at least have enough money to argue the case in court when the gun makers come after you.

I am not sure, but I think using military equipment and names is "free". I am not entirely sure, but in many games you see the military names of the weapon, and not the maker's. Could be completely wrong so.
I remember talking with a modeller about it, as he worked for a racing game, and they had no license for any car, so he made his own car designs, but they could use the military hummer (not the commercial h2 whatever...)

For legal advice, talk to a lawyer. Lawyer time is cheap compared to the stress of getting a Cease and Desist order (or worse).

As a rule, if another person or company has used it, developed it, or done something similar, ask them first.

If you aren't certain that you should do it, or if you have bad feelings about a legality risk, don't do it.

frob.

Quote: when the gun makers come after you.

Not people you want to piss off any time really.