Bout a month or so back ? Please tell me some of you CO air gunners had the good sense to try one. Seemed like a good way to de-tune a rifle for altitude. Hopefully he'll relist them so I wont have to resort to groveling.
He said he could make them up for the 97/77 too, n'that just sounded like good way to drop a 97 down, as opposed to souping a 300S up while making better use of the 97's stroke. Might make a good mini-sniping/Phut-Phut rig. Once you're over 5000 feet any springer over 725-750 fps. is pretty much a raucous waste of energy in these parts. 8 to 10 fpe. still covers a bit of ground in .177 ;^)
I pretty much make up my own stuff using different springs, so I don't really have any experience with that kit per-say. HW97's and TX's become pretty sedate at those power levels though. Problem is most today don't want it. More so if they only have the one rifle. It is very nice and the few that have had me do something similar were thrilled with it.