Controlled feed vs. push feed

[SGW42]

I'm hoping to get educated about this aspect of bolt actions.

I've read my Ruger M77 has a controlled feed mechanism but I can't find any more solid explanation as to what that means, or how it compares to a push feed.

Maybe folks have pictures, history, etc? TIA.

 

[JDGray]

Push feed....The exrtactor pops over the case head when you turn the bolt
Controle feed...The case feeds up behind the extractor while chambering.

I may be wrong, cause I always am (ask my Wife), but this is how I think it works

 

[dmazur]

I'll take a stab at this -

Controlled feed (aka CRF for "controlled round feed") guides the rim of the cartridge behind a large claw extractor as it comes up from the magazine. Sometimes the bottom of the receiver has to be tuned so this works smoothly. "Babying" the bolt as you work it can also cause trouble with some CRF actions, leading to jams. Others work smooth as silk, regardless of speed. CRF generally can't handle a round dropped into the chamber, as the claw extractor wasn't designed to snap over the chambered round. (Some CRF actions have been modified with ramped leading extractor edges and proper clearances to permit this.) Ejection is usually accomplished by a fold-down rib that pops up into a slot in the bolt, hitting the case at the proper point of retraction. The speed of bolt retraction can be used to regulate how far the brass is ejected. Mausers, original Winchester Model 70's (and Classic models), and Ruger M77 MkII's are some examples of CRF's.

Push feed just "aims" the tip of the cartridge toward the chamber and pushes it in. The extractor is spring-loaded and snaps over the rim as the bolt is closed. Ejection is usually accomplished with a spring-loaded pin, offset from the centerline of the bolt, which tosses the fired case clear as soon as its mouth clears the action. Speed of bolt retraction has nothing to do with how far the brass is ejected. Remington 700's, post-64 Winchesters and the tang safety Ruger M77's were push-feed, I think.

The argument as to which one is better will never be resolved. Each camp has its proponents.

 

[Geno]

Link to a video: http://www.youtube.com/watch?v=GZZphk6JWfQ

MidwayUSA — June 16, 2008 — Larry Potterfield, CEO and Founder of MidwayUSA, demonstrates the difference between a controlled round feed rifle action and one that is a push feed style action. Controlled round feed refers to an action that remains in control of the cartridge throughout the entire feeding process. As the cartridge is stripped from the magazine it slides up under the extractor and is held against the bolt face as it moves into the chamber. A push feed action, such as a Remington model 700, strips the cartridge from the magazine and uses it's forward momentum to chamber the round. The extractor does not retain the cartridge until the bolt is fully closed.

Geno

 

[Maverick223]

Here is a photo that illustrate the difference; the black one, on left, from Desert Tactical SRS, is push feed (henceforth referred to as PF) and the silver one, on right, from Whitworth Express Mauser, is controlled round feed (henceforth referred to as CRF):



Note that the PF design uses button type ejectors (the pictured one has two for redundancy, most have one) that are set into the bolt face, while the CRF design uses a blade (not sharp) built into (or bolted onto) the receiver to eject the casings. You will also note that the PF extractor is rather small compared to the large "claw" of the CRF design. This is hinged to allow it to snap over the rim, whilst most CRF designs are incapable of this function (making single-feeding difficult).

FWIW I prefer the CRF for hunting and the PF for target shooting, et al. The CRF is a bit more reliable and can be used inverted, but the PF allows for greater versatility. As noted the CRF bolt can be thrown slowly to "dribble" the cases out in a neat pile, or thrown with authority to ensure that the case ejects well clear of the port (and often several yards away), the PF design will throw cases to the same relative point each time.

To complicate things a bit, there are some hybrid actions that use a CRF claw, but have a ejector built into the bolt face like a PF. There are also PFs that have a fixed blade ejector rather than buttons set in the boltface, but the action is always classified by the method of insertion/extraction, not the method of ejection. If it "controls" (holds) the cartridge throughout the cycle it is CRF, otherwise it is PF.

 

[brandonc]

Controlled Round Feed is better, only you can decide if you need it.

 

[Maverick223]

Controlled Round Feed is better...

Not necessarily, most target/benchrest shooters would disagree with that. OTOH most DG hunters would agree with you. I ride the fence, and prefer each for different tasks.

 

[SGW42]

Very cool, thanks for the information.

 

[brandonc]

most target/benchrest shooters would disagree with that.

Yes, because benchrest shooters will pay for accuracy before they pay for reliability. The myth of CRF rifles being less accurate started because most CRF rifle's are intended as rugged hunting rifles, therefor are less accurate than custom bench rest rifles which are generally push-feed.

 

[bkjeffrey]

Just my .02. Having owned both Rem 700s with push feed and Winchesters with CRF I prefer the action of the CRF. My current go to rifle is an FN SPR A3 that uses a Win. Model 70 controlled round feed. I like the fact that I can control case ejection with the speed at which I work the bolt. I chamber rounds by hand and manually close the bolt on a loaded chamber most of the time. I have not had a single problem doing this, but the FN SPR is a very high end rifle, and I assume that FN incorporated the proper adjustments to do this safely. Another pro of the CRF action is the massive claw extractor. In my eyes this helps ensure positive engagement with the rim of the brass.
Ive cycled the action very rapidly as well and it feeds perfectly.

On my handloads I load my projectiles somewhat longer than factory ammo. This has proven to cause cycling problems for me in my Remington 700 actions. The CRF FN loads the longer cartridges just fine.

I prefer the CRF. Its smoother and more controllable in my opinion.

Also, the FBI adopted the FN SPR as standard issue for their sniper teams. Seems they favored the CRF Winchester action over any push feed action.

 

[Maverick223]

Yes, because benchrest shooters will pay for accuracy before they pay for reliability. The myth of CRF rifles being less accurate started because most CRF rifle's are intended as rugged hunting rifles, therefor are less accurate than custom bench rest rifles which are generally push-feed.

I didn't say they were less accurate ask USSR about accuracy of a CRF), it is just awfully hard to squeeze that massive extractor over those cases for single feeding the average CRF rifle (FNH SPR excluded).

 

[Slamfire]

The pictured Bernard Action is typical of an action optimized for target shooting. The only sidewall cuts are for the loading port and the trigger sear. The action walls are extra thick. Massive lugs and if you notice, no ejector.

The extractor is sufficient to remove cases from the chamber.

 

[nathan]

As long it shoots and works fine, i dont care what type.

 

[Ignition Override]

Lots of guys don't realize that classic (Yugo etc) Mausers require the rounds to feed from the magazine, otherwise the bolt will not close.

It made me think that the rifle required a gun smith, the day I bought my first Mauser (a Yugo 48A), a few months ago.
Somebody's quick response to a new topic question was a relief.

 

[unreal45]

Both work fine, but I prefer CRF. Just in case I need to shoot a charging rhino while doing a headstand.

 

[Maverick223]

Just in case I need to shoot a charging rhino while doing a headstand.

How else would you hunt rhino?

 

[Oceans]

The M1 Garand which was known to fire a shot or two in a hostile and rough environment is a "push feed" Somehow it managed to do OK.

 

[ArmedBear]

The M1 Garand

Irrelevant, for a number of reasons, which are clear to anyone familiar with bolt actions.

 

[Maverick223]

Irrelevant, for a number of reasons, which are clear to anyone familiar with bolt actions.

Yep, besides isn't nearly as reliable as a good bolt action (of any type), simply due to the sheer complexity of the platform.

 

[Sheepdog1968]

The one difference I recently learned had to do with an emergency reload in a combat/self defense situation when a bold action rifle is empty.

For a controlled feed bolt action rifle, you need to insert a round into the magazine well in order for it to chamber.

For the other type, all you need to do is plot a round into the open action area and close it.

Admittedly, this is a very subtle difference but I thought you might like to hear it.

 

[Oceans]

"Yep, besides isn't nearly as reliable as a good bolt action (of any type), simply due to the sheer complexity of the platform." Well in fact, the M1 was found to be the equal of the "controlled round feed" Rifle Caliber 30 M-1903, in terms of reliability among other criteria. Second, the M1 is a push feed design not a controlled round feed, of-course its not a bolt action, however it is important to point out the type of feed when we consider the feeding and ejecting aspects of the operation. I know some people are quite retentive about this issue, and it makes some very sore, but really the notion that you must have controlled round feed over push feed, or somehow you will "double clutch" and be eaten by a wild animal is simply overstated and bordering on preposterous. Very few of us will face a charging grizz or tiger, so lets take that out of the equation shall we. A big advantage with the push feed system, including the Rem 700 ( a primary example of the breed) is the ability to quickly insert a round into the chamber without having to precisely insert it into the magazine first. Another advantage of the Rem 700 bolt is that it supports the case head with that "ring of steel" 3 of them as a mater of fact.

For the VAST majority of hunting situations in the U.S.A, the fact is push feed is beyond adequately reliable and rugged, and the push feed actions do tend to be quite accurate as well. To suggest otherwise is quite honestly simply absurd.

 

[ArmedBear]

For a controlled feed bolt action rifle, you need to insert a round into the magazine well in order for it to chamber.

An antique, sure. Not my Model 70.

the ability to quickly insert a round into the chamber without having to precisely insert it into the magazine first.

Again, Oceans, an indication that you have no idea what you're talking about. Your 700 will work great for what hunting you do, I'm sure. I've got both types of bolties, and CRF is a better action for hunting on foot. A PF or single-shot will work, too. So will a muzzleloader, if you don't screw up. CRF is more tolerant of use under suboptimal conditions.

But the Garand, a clip-fed (not staggered-stack-magazine-fed) semiauto has no relevance to the discussion.

 

[bkjeffrey]

For a controlled feed bolt action rifle, you need to insert a round into the magazine well in order for it to chamber.

Not my model 70 either. I single load most all of my rounds and close the bolt on a loaded chamber.

 

[AMerexican]

Let's not forget the Good Ol' SMLE. Correct me if I'm wrong but it"s a CRF action and I've been single loadin' it for years, never a hiccup and it can be loaded upside down!

 

[Oceans]

Armed Bear, you make me laugh. Good on you, that you like your model 70, its a fine rifle, in fact I have one: but sir, please do not insinuate that those of us who use push feed actions are somehow under gunned with mechanically inferior feeding rifles, as compared to the controlled round feed folks, in the wilds, I assure you sir, we are not. I'm not quite sure that I comprehend what you mean by "hunting on foot" why should that matter in the slightest regarding the "push feed vs controlled round feed" aspect of the argument. Perhaps you think... I what, hunt from a helicopter??? At any rate my fellow hunter, this debate is as seemingly old as the hills, we both have our individual positions and I think we understand them, cheers!