The gun , unfired, opens itself to the full open position. When fired, the gun comes open somewhat less forcefully until it reaches the ejector trigger position. Then hand applied more opening trips the ejectors.
Sounds very similar to a rare Boss “self opener” system. Pretty rare mechanism. The answer lies with when you take off the lock plates and get a good look at the bar, you’ll be able to see the v-spring limb fitted into the bottom of the cocking limb/lifter providing the power for the self opening system.
A variation of the Edwin Smith easy opening system used on Churchill guns is also entirely possible. I mean the gun is, after all, an Edwin Smith gun!! Is it THE Edwin Smith though….the patentee of the easy opening system bearing the same name, or a different Edwin Smith? I dunno.
I could be way off too!!
