Hey Bartos, It looks like you are just missing a stock set, upperbarrel assembly, bolt, and a couple pins? The AR-15 type rifle is very modular and almost any AR parts will work on it. I don't know what the laws are in Poland, so I don't know what you will be able to import. Here is the Bushmaster website:
http://www.bushmaster.com/catalog_parts ... _index.asp
There are links to all parts and a diagram to show you what parts you will need. I shot a Bushmaster XM-15 a few days ago and they are very accurate little rifles. With a scope, I shot two 1" groups in the wind at 100 yards pretty easily.
Perhaps Afghanistan has lesser import/export laws and you can mail that home to Poland? Maybe you can ask for more parts there in Afganistan and send them ahead also? Whatever you are able to do , Stay within the laws of both places. Parts are made in China also for the M16/AR15 type rifles. Perhaps they have import agreements?
Good Luck and feel free to ask more Questions about this gun as there are several here that have them, and I am sure they can tell you exactly what parts you will need. Also, Ask and American G.I. , They may have some extras they no longer need. I have seen Claro Walnut Stocks for the AR15 and they are beautiful and make it look like the meanest rifle i have seen. My next door neighbor has the Bushmaster XM-15 so if there are any questions about how to spend $$'s to make your's look "fancy", I can ask him for you. haha.
Great to see you posting again! Please be cautious and Come home safe ! Garry