Yeah it is annoying. They all do it. It is the transfer bar that moves back and forth. Totally normal. It is actually mentioned in the owner's manual. Hope that helps!

Matthew, I agree. I would contact Ruger as this is not conducive to using this as a carry pistol. Maybe they know how to lessen of stop the transfer bar rattle. I have a transfer bar revolver and it does not rattle. Telephone: 336-949-5200 -- (Monday through Friday 8:00am - 5:00pm ET).

Matthew - you can thank the ambulance chasing lawyers who have hounded the firearms companies to keep adding more and more 'safety devices' .. when all that is needed is the only safety device that actually counts .. a disciplined trigger finger. As long as you aren't 'stalking' someone .. or sneaking up on anyone ... .. I doubt the rattle will be any problem while you are carrying your Ruger.