2-pounder recoil cylinder dimensions?

[Jakko Westerbeke]

It looks like there are some people here who own a real one of these guns, so I guess this is as good a place to ask as any: What are the basic dimensions of the recoil cylinder under the barrel of the 2-pounder antitank gun?

I’m basically looking for the total length, the diameter, the length of the domed end cap, and the lengths and positions of the bands on it

The reason I would like to know is this:

BARV gadget.jpeg

This is a Sherman BARV, and after much headscratching on various forums about what that thing’s purpose is, which was solved by the REME museum (it’s a shock absorber, for using a cable to pull things free when they’re stuck), I finally worked out it’s a 2-pounder recoil cylinder — and not 6-pounder, as I thought at first. But now to build it in 1:35 scale to go on this:

BARV model.jpeg

I have some photos I can estimate dimensions from, but it would be much easier if someone who has access to a real one, would be kind enough to measure it up