One of the theoretical advantages of the Mauser-type CR feed system is that the extractor is, to some degree, "cleared" of debris every time the bolt is worked.

In theory, a push feed extractor that must snap over the rim and into the extractor groove can accumulate enough debris to where it is pushed OUT by the rim upon chambering but does not snap OVER and INTO the rim, thus leaving the round in the chamber.

In the Mauser system, the case moves up under the extractor as the bolt is pushed forward, the rim of the case pushing debris up and out of the gap between the extractor and the bolt face.

This same process can result in clearing debris from the extractor groove itself as might occur with dirty ammunition. Dirty ammo chambered in a PF can in theory prevent the extractor from gripping the rim.

How much this is a real advantage of the Mauser type I can't say, but the mechanical advantage exists in theory if not in actual fact. To my way of thinking this may be more important than the CR action of the feeding itself, because I have had double feeds in Mauser types and in push feeds.

All Mauser 98's or 98-type rifles are not alike in that some gain control of the rim more securely than others or possess a magazine that maintains control of the round longer than others, allowing the rim to slide up under the extractor groove at the last possible moment, a good thing. I monkey with every rifle I own to find its "weak links" {ALL of them seem to have them...} and I have found the strong magazine spring of my CZ550 {a 98-type} causes rounds to pop up with some force and the rifle can actually be made {with some effort} to double feed by working the bolt slowly while jiggling the gun a bit. That in conjunction with the fact that the extractor does not snap over the rim in a dropped-in round makes for potential mayhem. Forceful bolt manipulation has never resulted in a feed problem with this rifle. I have mentally gyrated over the possibility of a fellow trying to work the bolt quietly while crawling or some such activity where the rifle is not level and stationary.

Having said that, it takes some effort to get this to happen with that CZ and the gun is otherwise very reliable.

With push feeds I've tested, working the bolt slowly while the action is listing to one side or the other, or jolting and not stationary, makes for a pretty easy jam if the round pops up out of the magazine while the bolt is given a slight back and forth movement which results in, of course, the classic double feed.

The shorter the cartridge, the easier the double feed problem in my opinion. My Savage .223 can be made to double-feed very easily. "Take that" you aficionados of the short mags!!

I'd way rather have the added length of my .375 H&H than a short stubby round of same performance due to this theoretical issue. Honestly tho, all of this is theory for the most part, but my problem with working a bolt is that I fear tearing it out of the rear of the action while working it fast more than short stroking it!!

Thus I would side with with longer rounds for a DG rifle for this reason if I was buying one.

All of these gremlins CAN rear their heads, but DO they? I suspect not often, but Peter Paul and the engineering staff at Oberndorf and possibly the ordnance fellows with das Heer thought it important enough to put time and effort in the design of the controlled round feed system.