A very long gun/musket I have. - Can you help Identify

[Blade]

Hello All,

I hope antique guns also fit this forum.

This one has a very long barrel, a strange primitive lock, the frizzen seems to have some wear on it.
The lock is almost stuck, I managed to move the hammer a few millimeteres using pliers, and then I stopped for fearing I might destroy this old piece.

The copper fittings are new, the other ones seem older, I don't know what material they are made of.

It was bought from a druze old man here in israel.

I thought it's quite unique untill I saw a gun just like that in the antique market in paris, at 2007. the shop was just closing, so I didnt get to ask questions about it, all I got is a picture from a cellphone camera.

I would like to identify this piece, perhaps even date it. and learn everthing can be learned about it.

Thank you
Yaniv