I spent the last week shooting prairiedogs with a couple of buddies and yesterday, to give the towns we'd decimated a break, we hit a small town near my house fit for rimfire shooting. One of the guys (Marine PMI of this site) had left the day before so we filled the slot with a local friend who brought his 22 WMR. The remaining out of state visitor had wanted to shoot a 17HMR so I passed him a Ruger 77/17 custom. After a sight in session, we headed for the dogs. The 17 was driving tacks. We didn't get many dogs, about 4 each due to the cagey nature of these hill country dogs.
An observation: The 22WMR with 40 grain HP CCI's knocked the dogs flat out to 150 yards. I didn't hear any audible ricochets and there wasn't any spectacular damage. The 17HMR just went clean through the dogs and kicked up dust behind them. All but one (head shot at 40M) made it back down their holes. There was hardly any indication they were hit until they thrashed themselves into their lairs. The 5mm blew them apart out to 156 yards (my farthest shot) but that was expected.
The results with the HMR were exactly what we (PMI and I) experienced the last time we took the HMR against sod rats. I even picked up new ammo for the shoot. It was very disappointing and my visitor wasn't too happy with the cartridge.~Muir