I went throught the compression procedure with the adjuster again last night after writing this post. This time I used the vise to hold the c-clamp vertically so the adjuster could be orientated in its installed position. The first couple of millimeters of compression there was little resistance then it firmed up. Like you guys have shared, from that point on it just sat there and every time I walked by I gave the clamp a 1/4 turn to tighten. As i turned the clamp the piston again would start off with having only slight resistance then would firm up at which point I would stop. Result was about a 1/4 turn of the clamp. This continued over a period of an hour or more until I was able to get the grenade pin in place. I never forced the piston once I felt resistance even when I had it in the vise the wrong way so it sounds like I didn't mess things up. The unit itself doesn't show any signs of being a problem (bearings or leaking). Thanks for your replies. First time for me using this forum.