CZ550 extractor issue

[rap36case]

The CZ550 is a mauser type action with the typical extractor. I recently had my CZ550 re-barreled from 308Win to 6.5 Creedmoor by a very fine young gunsmith. I also had the barrel threaded to 5/8 24 and cerakote in forest green on both the action and barrel with a 'special' lubricant coat on the bolt.
In the process the mirrored extractor went from flawless functioning to being rather loose. If the bolt is worked with authority, it functions fine. However, if the bolt is worked quietly and less aggressive, then the case drops on the magazine. Inspection on the extractor on the bolt indicates no obvious problem other than loose retention of a spent case.
Does anyone have experience with these extractors, and how to adjust them for better function?

 

[butchlambert]

The mauser type extractor only pulls the case out of the bore. The ejection is handled by a fixed part of the bolt release. The sharper you pull the bolt handle the further the brass is ejected. If it pulls the brass, it ain't the extractor.

 

[shortgrass]

If the extractor will pull the brass, but not hold it until the case head hits the ejector no matter how quickly you pull back on the bolt, it's usually just a simple matter of adjustment of the extractor.

 

[butchlambert]

If the extractor will pull the brass, but not hold it until the case head hits the ejector no matter how quickly you pull back on the bolt, it's usually just a simple matter of adjustment of the extractor.

How do you adjust a Mauser extractor? The diameter of the Creedmore is also the same as the 308 at the base.

 

[shortgrass]

You can adjust the tension of a Mauser type extractor by carefully grinding the protruding part, on the back side of the extractor, that fits in the groove near the nose of the bolt body. This allows the 'claw' to move inward, toward the center of the bolt. It usually doesn't take much and care must be taken or you will grind too much away. I just fit an extractor like this on a Dumoulin action that I barrelled with a Hart that I chambered in .280 AI. Even though the head size is the same for the .308 Win. as it is for the Creedmore manufacturing variations do exist making for less than ideal extraction to ejection in the Mauser system. I usually don't see this condition on surplus military Mausers or individual surplus extractors I might buy as they've already been 'fit' when assembled as complete rifles. I've not seen it in the Interarms MK X or those Charles Daily imports, but I've used several of those (Sarco) Dumoulin actions that needed their extractors fitted so they'd have enough 'grip' to make it to the ejector and I've used this 'fix' on several CZs that were dropping the case on the follower/cartridges in the magazine before they'd make it to the ejector. (I usually don't give out 'honest to God' gunsmithing tips on any forum, but I'm feeling generous this evening!)

 

[shortgrass]

Here's a pic showing where to grind. Be careful, it'd be easy to grind away too much.

 

[rap36case]

You can adjust the tension of a Mauser type extractor by carefully grinding the protruding part, on the back side of the extractor, that fits in the groove near the nose of the bolt body. This allows the 'claw' to move inward, toward the center of the bolt. It usually doesn't take much and care must be taken or you will grind too much away. I just fit an extractor like this on a Dumoulin action that I barrelled with a Hart that I chambered in .280 AI. Even though the head size is the same for the .308 Win. as it is for the Creedmore manufacturing variations do exist making for less than ideal extraction to ejection in the Mauser system. I usually don't see this condition on surplus military Mausers or individual surplus extractors I might buy as they've already been 'fit' when assembled as complete rifles. I've not seen it in the Interarms MK X or those Charles Daily imports, but I've used several of those (Sarco) Dumoulin actions that needed their extractors fitted so they'd have enough 'grip' to make it to the ejector and I've used this 'fix' on several CZs that were dropping the case on the follower/cartridges in the magazine before they'd make it to the ejector. (I usually don't give out 'honest to God' gunsmithing tips on any forum, but I'm feeling generous this evening!)

 

[rap36case]

Thank you very much for your enlightening comments! It makes sense to me now that a couple of thousandths can be removed from the area you mentioned to obtain the retention. Further, this bolt and extractor were recently coated with a lubricating, dark gray material to mask the shininess of the extractor. It is quite possible that the coating only needs to be removed from these areas to restore function. I will try your suggestion by gently sanding and cleaning this area.

Thanks again for everyone reading and responding to my questions!