Shoottothrill:
Not sure, I don't have a full size IPSC silhouette in my steel collection. The largest steel piece I have is 24" x 36" AR500 for load development for some margin of error and the farthest I've tried ranging it was at 1200Y-- didn't have any issue. Also didn't have any issue getting on a 12" x 24" plate at the same distance. My smaller 45% IPSC silhouette and also a Big Dog reactive head/chest target at 1100Y also wasn't much of a problem provided the binos were steadied on a tripod, freehand use at that range was maybe a 50% success rate.
Regarding the cows, my old 1600 Fusions were near 100% success rate out to 650-700Y and started dropping off from there, I don't think I managed any readings beyond about 850Y and beyond about 750Y it took numerous tries to get a return. The 1 miles were near 100% out to about 900-950Y. I managed to get ranges on some cows out to about 1200Y but I'd say that was about a 40% success rate and you had to have them steadied on a tripod.
One thing interesting about the Bushnells is their beam divergence is rotated 90 degrees compared to the majority of other rangefinders on the market-- it's a "tall & thin" stripe rather than "short and wide" stripe. With appropriate use of the bullseye or brush modes they seem to pick up smaller targets better than other rangefinders on the market with similar beam divergence specs because of that 90 degree rotation.
