Controlled feed actions are those in which the cartridge coming from the magazine and being inserted in the chamber is somewhat locked into the bolt – held by the extractor – from the time it is free of the magazine, during firing and until free of the arm. Where upon the bolt ‘grabs’ the next cartridge in the same manner.
As with most things there are two major camps of rifle enthusiasts. Probably not as staunch as large versus small calibers, but still a distinction. Bolt action rifles are – a single distinction, not a combination of factors – into ‘controlled’ and ‘push’ feed systems.
Push feed actions are those which the cartridge in the magazine is merely pushed from the magazine and into the chamber. If not before, the extractor ‘snaps’ over the rim of the cartridge upon chambering. The extractor then extracts the fired – or unfired, as the circumstance dictates – cartridge from the chamber.
The controlled round function has existed since the late 1800s, 1880 or so (I’m not really sure of the date, and I do not find that information important). The push feed type rifles have existing long prior, as any rifle which can be loaded by dropping a round into the mechanism must then have the extractor ‘snap’ over the extractor rim, groove or whatever. So any single shot or rifle with a magazine cut off is push feed unless a rather complex mechanism is involved. I don’t know of any, but I’m not God nor Batman. By the same token, controlled feed rifles are those that are feed only from a magazine.
The controlled feed system was developed for primarily military use. This was in the day of infantrymen being equipped with bolt action rifles and transitioning from selected single shot fire to magazine fire as the officer in charge decided. Controlled feed was considered important for at least two reasons:
A controlled feed rifle can ignore gravity to some extent. Operating the bolt will chamber a round (presuming cartridge or cartridges are in the magazine) in awkward positions. Like shooting from prone in an irregularity in the terrain. Or hanging upside down from a tree.
Reason number two is far more defensible. If one ‘short strokes’ the bolt – that is, does not retract the bolt far enough to eject the fired cartridge – with a push feed, the next round in the magazine will be pushed by the bolt forward creating a ‘double feed’ malfunction and ‘jam’. That cannot happen with a controlled feed mechanism. Since many armies used young men, the tendency to panic was extremely possible when under fire. So the controlled round design was less likely to have that jamming problem.
One notes that nearly all semi and fully automatic weapons currently are push feed. The human factor of not properly operating the bolt doesn’t exist.
So, which is better? Pretty much all bolt action rifles in the current era are for sporting purposes. Battle is now replaced by the possibility of a rather enraged, clawed, toothed, hoofed, just plain huge or some combination thereof. A controlled feed action might be preferred for those times.
But for any occasion, if one retracts the bolt back fully: the fired cartridge will extract and the next round will chamber (presuming the chamber is relative free of obstacles). Then, move the bolt forward, smartly, completely and expeditiously. One might train and condition one’s mind and hand to perform in that manner.