I have a 22 caliber pump rifle manufactured by The National Firearm Company MARTEL stamped on the 20 inch barrel with no serial numbers anywhere and I am looking for information and value?

I also have a Martel 22 cal. pump. Does yours break down with a screw located by the trigger and reciever? I just brought mine in to fix the bullet alignment piece located at the top of the reciever. Let me know if you get the answers to your questions, I have also wondered if it was rare or common.