.400NitroExpress

Now I am confused !, Did Lancaster build it ?
If it is not a Lancaster is it an Osborne ?

Please clarify.
It looks like the one in the picture, except it las a lever type forearm latch, no stalking safety.
The strikers are bushed from the top with a dovetail not disk type bushings.
May have been done later !

Thanks
Nitro450exp