Right, so I got that little extra time and spent today with a small file.....

The Viper now sits very handsomely in its new B Square mounts atop the HW100.

A couple of my own tips for anyone else contemplating these things.
1. Once you have filed the holes to allow clearance for the cap screws to bite cleanly into the bottom of the mount, fit the mounts to the scope first, not the rifle. Its a fiddly job and being able to hold the scope made it easier.

2. Keep everything loosened and slide the scope, on the mounts, carefully onto the dove tail. Any doubts about loosness or security of fit will vanish as you begin tightening.

3. Tighten the mounts onto the dovetail/rail first, then tighten the caps, that will set the mount tubes at your pre selected angle and lastly, nip the windage grub screws, this clamps what I earlier thought was a thread tolerance problem.

A couple of issues with these mounts.

1. Filing the cap holes will set the screws 'off centre' so they wont sit correctly in the countersink and if your analy perfectionist like me, you wont like how this looks.

2. Zeroing the scope using the mounts MUST now entail removal of the scope along with mounts from the dovetail/rail for each adjustment. lengthy, but by the look of things it will be worth the effort and should be a one off.

Ill let you know how they zero when I get done at Petes farm on tuesday if you like.

Chairgun is suggesting an optimum zero of 40 yards for the height of the LOS above the bore centre so Im going to give it a go

Cheers
Barry