Is this a Knight MK 85 Scope base?

[RecoilRob]

Some years ago I got a bunch of Warne scope bases, this was among them. It's only stamped "89", I thought it might be for a large revolver but it's been suggested to me that it might be for a Knight 85.
Unusual in the fact there are 5 mounting holes and three positions to mount rings.

Is that notch in the bottom help ID it? It would face left.

 

[GM54-120]

This is Knight spacing for all but MK85s.

 

[sabotloader]

I think the hole spacing is exactly the same across the Knight inlines. The difference in the MK and the rest of the inlines is the MK line uses a flat to receiver while the rest use a rounded receiver.

You can see the flat top in this pic.

 

[tpcollins]

Looks long with a small opening for the breech plug area.

Here’s mine that I never used.