The older Uncle Mike's grips work perfectly with an HKS speedloader. The newer factory grips feel good and look good but are not relieved enough and sure enough will easily lock a speedloader up tight. I too wonder why S&W has not corrected that. Hogue Bantams work quite well but I don't like them as well as Uncle Mike's. (They are a bit lighter, though.)I've never had a problem with HKS speed loader clearance with the stock boot grips that came on my 642.