Recently got my 44 mag barrel and 22 hornet set up. After some shooting and settling down at 50 yards the hornet would shoot 3/4" groups and the 44 about an 1 1/4". I wanted to do a bit better than that. Put on the o-ring on the 44 and got clover leafs, the hornet instantly went to one ragged hole. Took them all apart, put them back together with the o-ring again, same zero, same results. O-rings are now mandatory. I had used them in my 270 and 45-70 with good results but I thought with the heavy hornet barrel that it wouldn't make much difference, wrong. Oh yes, 44 mag: 200gr Hornady with EDITED: 28.5 grains H110 approx 2100 fps. 22 hornet: 35 gr V-max with EDITED: 12.3 Grains H110 approx 3060 fps via 2006 hadgdon manual. Fun to shoot too! :-)