Another post said about changing the extractor collar on the CZ550’s. I read an in depth article once advising the same. Something to do with the new versions being pressed metal but the original Mauser were cast or formed differently. Something they said was they have an effect on how smoothly the actions cycle.Something Mauser got right. It points out people shut a lot of effort into polishing rails and slicking actions and this little clip can make a world of difference. Secondly, do they make a pop up aftermarket peep sight for the CZ550? It seems that it is a desirable feature of the Brno 602. Why not offer an after market version What other small improvements can we do on a budget? I can’t afford a full custom but I. Like to tinker with my rifles. I have bedded most as I can do that myself I polished the bolt and rails on my first Cz550 but I sort of shelved it and haven’t chased a extractor collar.