Whats a good tune for an HW85k ?

[sd5782]

I've never owned the early '85, John, but were they 25mm?

You will know better, as you will have, no doubt, owned / worked on these, but if it's not a silly long stroke maybe best left with the standard dimensions?

My main concern would be over the cutaway at the top of the rear of the piston to create clearance for the scope ramp. My guess would be that, at the very least, a tune should ensure that there are no sharp edges left in this area and an application of high content moly paste to protect against any potential wear.

I think the V-Mach kit includes a replacement (exchange?) piston with a synthetic band at the rear?

My Beeman R10 which is the same as the 85 Mk1 has a stroke of 89mm vs 85 for the R9 or later 95. The piston is also a bit lighter with the cutout at 260 grams vs a bit over 270 for my R9. In full power tune over here in the states, the R10 makes 14+ ft/lb easily with only .120 wire spring and has a more pleasant shot cycle although requiring good technique and follow through for best accuracy. A lazy feeling shot cycle.

I was a bit surprised at the difference there was with only 4mm longer stroke. My HW77K on the other hand is 4mm less stroke at 81mm. A different animal altogether though with its short TP and the sliding cylinder. Much quicker shot cycle. Easy to hit with, but not as pleasant.

[Clanchief]

Short stroke nose ~10mm, tinbum properly fitting guides.

This is what I fitted to mine.