Just eyeballing where the ogive starts, I'd estimate that somewhere between 10% and 20% of the bullet's bearing surface is in front of the cannelure, and thus the total bearing surface of the bullet has been effectively reduced by that amount. I'm a little weak on internal ballistics so I don't now if that change will have much effect on trajectory and accuracy, as opposed to changes in neck tension, powder charge, crimp, etc. Assuming I wish to take the time to measure each bullet and adjust my seating die to make sure the bullet bases are the same distance from the case head as the safe load I've worked up, and check to make sure the nose of the bullets thus seated don't protrude beyond the front of my revolver's cylinder, is the deformation of the bullet nose likely to create much discernable difference in performance? For use as practice rounds I think they would be fine since I probably can't shoot the difference. How about shooting them over my chronograph? Is it likely that velocity will be affected much by the reduced bearing surface? I'm too cheap to throw them out.