MP40 or Vigneron magazines in a Lanchester

[tankhunter]

Jim, I have to admit. I have never used a C1 Mag in a Sterling L2A3, so cannot comment.

I THINK I have at least one Canadian C1 Mag in the Collection. But as my 'storage Facility'.
Is full from floor to ceiling, with only a 2.6" gap down the centre. locating pretty much anything these days. Is a Major 'Exploration' in itself!.....

Just to add to the Mix. Whilst in THEORY, that certain models & various manufacturers of Magazine. Are actually interchangeable in certain Weapons in the SMG Class of Firearm.
In practice, it will be frustratingly discovered. That some Mags of identical pattern, WILL function. And some will not. This is due to manufacturing tollerances in the external measurements of the magazine & also the internal dimentions of the Mag housing. If you have for example, a Mag at Maximum Tollerance. & also a mag housing at the same allowance. It may be either a very tight fit. Or will not enter the housing fully at all without FORCE.
Which is something you should never have to do, when firing any weapon!

this is ONE of the reasons that differing classes of Weapon. May be encountered with matching serial numbered magazines to an individual weapon. so they are a known & tested magazine to that particular weapon.
The German Luger is the first example of a handgun that springs to mind.. A similar situation exists with bayonets as well........