Or to be precise ".22 Premium High impact slugs", 17.8gn at .217", with a BC 0.048. cost £18.33 for 100 post free from pro-hunter.

I saw these advertised as suitable for sub 12fpe rifles so decided to give them a go.
The quality of manufacture & presentation is superb, they actually come in a little velvet "jewel" bag inside the tin,
on the scales every one was between 17.6-17.9gn, they are also washed before dispatch so not a grain of swarf/debris to be seen.

They were tested in my .22 Rapid MFR, 19" barrel, which usually shoots JSB Exact 16gn in to 1/2" groups at 25yds.

Initial zeroing was at 20yds, into a box of old magazines so they could be recovered for inspection,
As it turned out at 20yds the POI was the correct height & slightly right of the JSB's 25yd zero, 5p size groups, the chrono gave an average of 520fps for 10.6fpe, (574pfs 11.63fpe with the JSB)

I then went to my garden 'FAC' range at 42yds, Chairgun said POI would be 4" low, & sure enough it was, half a rotation of the turret sorted the height, it had pulled to almost an inch right, so gave it 8 clicks over.

It shot a mag of 12 into a single 5p size hole, with 2 flyers which were more than likely human error, as the rest slipped a couple of times.
I followed up with a mag of FX (JSB) which gave a group of 1.5" in the gusty wind.

Accuracy wise these are obviously excellent even in today's gusty wind, Can't wait to try them on a still day.

I then fished out the pellets from 20 yds to check the expansion, basically there isn't any ,
as the photo shows those that hit each other crumpled, as does any pellet, but those that didn't show little or no sign of expansion.

Conclusion,
I'm still sat on the fence.
if you were regularly shooting 40-50yds, &/or in iffy conditions, the increased accuracy would probably be worth the cost, but if you restrict your range & weather conditions, that's a lot to pay,
500 slugs are 4p shy of £72

I bet these are stunning in FAC 25-30ftlb's