My .25 Veteran did not like regular 25.39 kings all that well, so I ordered some heavies in original and mk11. I set the gun at 880fps and they shot horrible, about 2 inches at 60 yds. This was with the original heavies. Did not have much faith that the mk11 heavies would do much better because I really did not see but a slight difference in the rear ends of the pellets. At 60 yds. again I was shocked to find that the mk11s grouped pretty much as well as I could hold them. Just getting started tuning this vet so have a lot to try, I dont really know yet how fast this gun will shoot them, but the mk11s will easily shoot groups around 3/4 in. at 60yds at 880fps. It is just hard to believe there is that much difference in these two pellets. Has anyone else had a similar experience with these two pellets ?