Do you know the origin of these 1951's? Curious if they are Israeli surplus or not.
The ad on your websites lists these guns as having 10-shot magazines. The original 1951 models had 8-shot magazines only. The 10-shot magazine was introduced with the select-fire 951-R (Raffica) model, which saw short-lived production. Are you certain these are 10-shot magazines rather than 8-shot units? Please confirm.
Do you have any spare magazines (of any type) for these guns?
Are these single column magazine? How many come with the firearm?
Youtube answers!
https://www.youtube.com/watch?v=-KqVmjCwT8Q