Last year I bought a brick of them, because my interest was peaked by the exceptional amount of heat (MV) they are claimed to carry (1750, IIRC). At the time, there wasn't much response to a post I had made asking others' opinions on how the rounds were performing for them. I guess they weren't on the market long enough at the time. So I said that I would post up my own results, after I shot some of them up. I haven't done too much shooting with them since then, but here is what I DiD up with: First of all, you can tell-by-the-smell (sound also), that they are not your average HV (1260 - 1290fps) rimfire rounds. They give off a very potent plasticy, highly "synthetic" sort of smell. Maybe that is due to the highly-bragged-up Eley prime charge that they use. Performance wise, they DO deliver. With the marlin sighted in at 50yd, using regular HV rounds, POI is about -3" at 100yd. If I then chamber a supermax and take a shot at 100yd, the POI will be at +6". That's a total of 9" of elevation gain! Uh, am I wrong to think that that is impressive? Accuracy wise, they are more finnicky when it comes to a dirty bore. That may be due to them being 6gr lighter than the standard HV rounds. With more frequent cleanings, accuracy is equal to or greater than the regular rounds, most notably at longer ranges. That's it for the time being. Terminal data will be provided as soon as some becomes available.