Hunterapp, who did your 527 re-barrel work?
Pacnor did the drop in barrel per my request. 22" factory sport contour.
I removed the original barrel. A good barrel vice & action wrench were purchased for this task. Still a real pain to break loose the factory barrel. Factory barrel & action are blued together. The bluing salts tend to penetrate everything & as it works out the threads become very difficult to release.
Actually initially removed the barrel to convert this rifle to 6.5 Grendel a couple years B4 the factory 6.5 Grendel offerings were available. That barrel was a Lothar Walter barrel sourced off E-bay believe it or not:)
Ordered a 6mm ARC Go Head space gauge. Threaded the drop in barrel & bolt would not close as the relief for the extractor was insufficient by roughly .015". Fortunate to have a friend with a lathe. I increased the extractor clearance by .025" as I recall, to insure extractor clearance. Threaded the barrel in the action good & snug. Checked the head space with tape on the go gauge. One thickness of tape on the head of the go gauge made for a snug lock up.
Also have a Whidden micrometer head space gauge to measure brass. Fired brass turns out to be right at .003 longer than nominal, per the Whidden gauge. First custom lapped barrel for me. What a difference.
Have a Varmint contour barrel made by Pacnor arriving soon for the CZ. We will see How that new varmint barrel fits up & shoots before long.