<html> At 08:07 AM 05/14/2001 -0400, you wrote: <blockquote type=cite cite>collapsed state - quite unlike when hooked up to an air supply. Anyway, in this condition, the collar does go down to the coil and actually rests upon the coil. I guess I have to say that I don't know exactly how it rides the pin top during use. But I can say that I pounded a couple hundred pins with string coils into a pin block with complete success using the tip as it came with the Nailer as-is.</blockquote> A suggestion: Get a magnifying glass and inspect the becket.  If there is a ding in the wire made by the impact hammer then you need a shorter collar.  This could cause a broken becket down the line, especially detrimental to bass strings in the event they need to come off the bridge, the becket is compromised and will break. Regards, Jon Page,   piano technician Harwich Port, Cape Cod, Mass. <a href="mailto:jonpage@mediaone.net" eudora="autourl">mailto:jonpage@mediaone.net</a> <a href="http://www.stanwoodpiano.com/" eudora="autourl">http://www.stanwoodpiano.com </a>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</html>