HW50s (HW99) .20 calibre project success

[bokes]

If you fancy both the HW99 & the .20 calibre, you might find it interesting that my tuner was able to install a .20 HW95 barrel/breech block onto my .22 HW50s with a few tweaks (I think your UK HW99 is identical to our HW50s). The cocking link from the barrel block to the piston had to be slightly shaved down 7/1000s of an inch on both sides to fit, and in one spot in the stock had to be slightly sanded down in the cocking-arm slot to provide a little extra room for the taller breech block.

Works great, I'm getting cloverleaf groups from the bench at 25 yards using H&N Ftt pellets. The Vortek kit is doing 13 fpe. I think the slightly longer barrel makes the rifle a tad easier to cock too.
If you'd like to do the same, take note that my tuner said the dimensions of these parts have changed over the years or are subject to change. Both the .20 barrel/block and my HW50s were purchased new in 2016.

Why not just buy a .20 HW95? I tried a HW95 detuned to 12 fpe but wasn't impressed, the firing cycle felt too long & mushy. The 50s has a quick, sharp, satisfying "whack". The HW95 with the FAC spring is a crackin' gun but to me felt too powerful for pesting around the house, & finally I prefer rifles that are shorter/lighter and less hold sensitive.
Why go thru all this effort? I liked the firing cycle of the larger caliber, & want fewer pass-thrus than a .177 when pesting, and at this power level wanted a flatter trajectory than the .22, so basically I wanted a compromise.
Was it worth it? For me, absolutely. I only want 1 'do it all' springer and this is my prefered springer power, caliber, & rifle. On the way is a CustomStock & Rowan trigger from the UK. Can't wait!

http://i99.photobucket.com/albums/l3...W50s_20Cal.jpg