Only had 2 over the years - one was a Ryland and Sons 1939, essentially the same as this:
http://www.ebay.co.uk/itm/like/17214...508&rmvSB=true
The other was similar, but non-military. Both suprisingly good to use on axis, but with harsh spherical abberation off axis.
I suppose they don't totally qualify, but they are brass tubes, albeit leather covered.