Tested Griffin slugs in .217 and .218 in a Lothar walther choked barrel specs are for that barrel .215 lands and .221 groove ..217 is too loose and shotgun ...218 fit better but are inconsistent...Conclusion...stick with a decent pellet that has a skirt that engages the grooves..Barracuda 18.52 are Lazer accuracy for the lothar walther barrels..in .22 magnum springers..spent 8 hours in the field today testing the slugs weights from 16 grain to 20 and they do not group like pellets do .went on a light hunt after testing and switched to the barracuda at 18 grain and hit 4 squirrels at 50 and 65 ...The jury is out slugs are a waste of money to accurately shoot out of a springer. back to R&D to make a slug that can shoot minute of squirrel at any range ..