Just gave these a quick test in the hw98. Cleaned the barrel and put about 20 through before any testing. They are very very tight in my barrel. Due to being of very hard material. Over the chrono this showed as they came out at about 760fps. Mozzies come out at 805fps, JSB exact 780. So not very efficient in the HW.
Groups are not worth showing. Only tried at 25 to see if they would 1 hole. Quite erratic. Sizing with a 4.52 die helped a little producing 1 1 hole group out of 3 about 2 pellet widths. Mozzies and RWS do less than this effortlessly in my HW so I will stick to these. Will try them in the PT.
Also I had very black fingers after my test, suggesting that although shiny they may be lubed or oiled like accupell. I get slightly grey fingers after weighing a tin of JSB's but this is black.
Bit more testing. Sizing with a 4.51 die produced much better groups with 10 shots going into about 6mm ctc @ 25 yards. Very hard pushing some of them through the die, some even produced a slice of swarf cut by the die, they are that hard/brittle. Sizing dropped fps further to 750fps making them just too inefficient in my boinger. The weights are very good though. No Die/batch numbers on the tin.