I'm afraid that on a sales thread you have to put a price (as you have done) even if you are unsure of the value and cannot ask for offers.
As to the value, we are not allowed to comment on a sales thread, which this is, so I can't say anything except to point out that it is not a BSA you have for sale but some sort of Langenhan/Pulvermann/Millitia-style pre-WW2 rifle.
I suggest you start a new "what's it worth" thread and once you have an idea of value come back to this thread and amend your asking prices accordingly.