H&N rabbit magnum pellet accuracy

As I've posted previously, I have tried the Rabbit Mags in 3 guns: A stock Hammerli Pneuma producing around 30 ft-lbs; an highly-modded .22 Marauder producing just shy of 60 ft-lbs; and an highly modded .22 Condor SS producing 65 ft-lbs. All three shot patterns instead of groups. On the cover of the tin H&N has a graphic listing the "precision" and "distance" potential of the pellet; distance is represented as 5 out of 5 (I'm inferring they're saying that the pellet carries its momentum well which would be great for what you're asking); but "precision" is graphically represented as a 3 out 5. So even H&N admits they're not going to be accurate relative to other pellets. A real disappointment since the "bullet configuration" just screams long-range potential.

I found the Promethius Piledrivers (a boat tail slug design), while not match grade accuracy, did better. The Marauder seemed to like them fairly well; they grouped just over 1/4" at 25 yards. So I would recommend you try those over the Rabbit Mags.
 
Well, either of those rifles would have the muscle to fling a pellet such as this. I would advise caution with the Hatsan, as personal experience (and many reviews) have clued me in to the fact that Hatsan Barrel diameters tend to run to the small side of tolerances. Since Rabbit Magnums seem to have trouble with barrel jams anyway, I would be leery. I will note, however, that H&N Sniper Magnums are the preferred food for all three of my rifles (Gamo Silent Cat, Hatsan 155 Vortex .177, and Hatsan 135 Vortex ..22). A bit less weight, true, but more than enough knockdown power at the point of impact. They're basically a diabolo/slug hybrid.
 
With different .22 PCP rifles and barrels up to about 875 fps, accuracy has been dreadful. With one choked barrel I would get maybe 20% of shots that landed on top of each other but the rest were flying all over the place. I tried sorting them be weight and size (length/head/waist) but no material conclusions. Have emailed H&N a few times but never received a reply about them. I add hat H&N replied to emails about other pellets that I said were either excellent or needed a slight design change. At present, other than melting down for bullets or fishing weights, I cannot think of a practical use for them.