I have been using both, the kleen bore and Triple Seven and have not noticed any difference in accuracy. I have also heard to switch back to No.10 caps, I have breechplug addapters to add the No.10's to the 209 but have'nt tried this experiment has anyone? Then again I've heard you need the extra umphhhh from the 209's to properally ignite the pellets. Who's right??