Yes..

The guides were snapping right at the flange. I had them thicker,thinner and even made a steel washer for the spring to sit on. With the R6 spring it worked out in every case but the two piece guide. I think it allows the spring to flex too much. But the Apex is a different story, that bad boy would eat them all. Steel was the only thing I could get to work (never made them from brass though, just steel and amco) To be honest at first I didnt like the Apex spring but once I got everything lined out its smooth as butter and a joy to shoot. I really like the end results. Not as smooth as the TX200 when cocking it but just as nice when firing. I figured that was probably the best I could do and been shooting the heck out of it ever since, up untill I got bit by the QB, R9 and PCP bug. But I do find myself going back to my B40 here the past few squirrel hunts! (too cold here for co2 right now, the R9 has had its fair share of rounds and my PCP--well I just ordered it..LOL!)
Looks like it up to you to figure out where I went wrong! Hopfully youll get it. Almost forgot, I also maghined the compression chamber for a delron bearing (like the two thats on the piston) Really helps smooth it out when cocking it.....