Home Forums Hunting & Shooting Ask The Gunwriters Mid-JUNE column: Controlled-Round Feeding

CONTROLLED-ROUND FEEDING

By the 1980's, new controlled-round-feed rifles were just about non-existent in the United States. There were exceptions, but all major American-made bolt-actions were push-feeds, including Brownings, Remingtons, Rugers, Weatherbys and the former poster-child for "CRF," the Winchester Model 70.

But in 1990 a new Winchester Model 70 appeared, supposedly bringing back the idolized pre-1964 version. This wasn't quite true, since the new 70's action had slightly different action dimensions, identical to the push-feed version made since 1964--but the dimensions were also more consistent, thanks to modern manufacturing. This second coming of the original Model 70 featured a long, Mauser-style extractor along the right side of the bolt, to most shooters the primary identifying mark of a CRF--even though the Ruger 77 had one too, yet was definitely push-feed.

In fact, in 1990 very few American shooters actually knew what controlled-round-feed meant, or cared, but after Winchester's new/old rifle appeared, the basics of CRF were explained in many magazine articles, over and over again. They had to be, to give the ignorant modern generation a crash-course. For those who missed these explanations (perhaps because you were too young to read), here goes:

In a push-feed bolt action, the extractor doesn't grab the case rim until the cartridge gets pushed into the chamber and stops, forcing the extractor to pop over the rim. Before the extractor grabs the rim, the round is essentially loose for a brief interval after it moves forward out of the magazine. If for some reason the shooter retracts the bolt before the round's chambered, the cartridge just lies there, like a hot dog on top of a mustard-free bun (unless, of course, the shooter tilts the rifle, whereupon the cartridge can fall to the ground).

If the shooter tries to bolt another round into the chamber while the loose round is lying there, the bolt-face also pushes the next round in the magazine forward. Obviously two cartridges won't fit into one chamber, so the rifle jams. This is called "double-loading," and considered the primary flaw of push-feed actions.

In a CRF action, the rim of the case slides up under the extractor as the case rises from the magazine, so is "controlled" by the bolt-face and extractor during its journey to the chamber. If the shooter retracts the bolt before the round chambers, the extractor pulls the round back, and the ejector pushes it out of the action, The shooter can then push the bolt forward, chambering the next round in the magazine.

CRF was the rule rather than exception in military bolt-action rifles from the 1890's onward, because it theoretically prevented panicked soldiers from "short-stroking" the bolt and causing a double jam-up. The dominant extractor was the long Mauser-style, so named because it appeared on every bolt-action designed by Peter Paul Mauser from 1892 through 1898. Essentially a long, stout, flat spring with a hook on the front end, the Mauser extractor was attached to a steel ring around the bolt called a collar, and slid along the right raceway of the action. As a cartridge rose from the magazine, the rim slid upward behind the hook.

This system prevents double-loading--usually. If the bolt of a CRF action isn't withdrawn far enough for the ejector to push an unfired round out of the action, and the shooter tries to chamber the next round, the edge of the bolt face can also start the next round forward, causing a jam. But this is far rarer than double-loading a push-feed rifle.

The Mauser system also resulted in a very strong extractor, which grabbed a big section of the rim, important back when smokeless powder was relatively new and pressures varied considerably. The big hook helped yank stuck cases from the chamber, and if for some reason the extractor broke, could be relatively easily replaced by sliding another onto the bolt collar.

In fact, the Mauser system worked so well many other military bolt-actions essentially copied the same basic system, including the Japanese Arisaka, 1917 Enfield and 1903 Springfield. As more bolt-action sporting rifles appeared, many featured the long Mauser-type extractor, including the Remington Model 30 (a civilian version of the 1917 Enfield) and the Winchester's Model 54 and 70.

However, this does not mean all other bolt-action rifles, both military and civilian, were push-feed. Some were, but many were CRF, though with much smaller extractors, often resembling some push-feed extractors. The famous 1903 Mannlicher-Schoenauer action, for example, is controlled-round feed, but with a small, spring-loaded extractor on the right side of the bolt-face, rather than a long Mauser-type.

Automatic and semiauto military rifles used various extractor systems as well. Perhaps the most familiar to Americans is the CRF system used in the M1 "Garand" rifle, which began as a project headed by John Garand in the 1920's, and was finally adopted by the U.S. Army in 1936. The Garand uses a small, spring-loaded extractor, but is still controlled-round feed.

Many recent bolt-actions use variations on the Mannlicher and Garand CRF systems, including several limited production rifles from Fierce Rifles and Legendary Arms Works, as well as major manufacturers such as Sako and even Winchester. The Winchester Model 70 action for the Super Short Magnums was called a "controlled push-feed," a mixed way of describing what is definitely a CRF action.


Bolt actions don't have to use the long Mauser-type extractor to be controlled-round feed. Here are a couple of examples, on the left a bolt from a Legendary Arms Works Professional Rifle, and on the right the bolt from a Model 70 Winchester action for the Super Short Magnums.

As a matter of fact some other rifle actions are CRF, with the famous Savage 99 a good example. The 99, however, doesn't use a Mauser-type extractor, but a much thinner and shorter version that, of course, doesn't rotate around the bolt, since the 99's bolt simply slides back and forth.


Rifle actions other than bolts can also be CRF, such as the Savage 99. Here a .358 Winchester round rises from the rotary magazine as the rim of the case slides under the extractor.

Yet somehow many hunters believe ONLY bolt-actions with Mauser-type extractors are CRF, but most such rifles don't actually use every detail of the Mauser system. Yes, they have the long, rotating extractor, but a tiny but important Mauser feature is missing.

In a long-extractor CRF action, a slot encircles the bolt behind the bolt face, just in front of the locking lugs, where a “tongue” of steel fits, as Stuart Otteson calls it in his book The Bolt Action. The slot and tongue keep the extractor from sliding back and forth on the bolt body, but in the 98 Mauser the back edge of the slot is undercut at an angle, and the tongue is angled forward to match. When a fired cartridge case resists extraction, the angled tongue wedges into the undercut, firmly pressing the extractor around the case rim.


Here's the illustration of the extractor "tongue" undercut on the 98 Mauser. The bolt's from my CZ 550 Magnum in .416 Rigby, which includes this feature.

In almost all other long-extractor CRF actions the slot and tongue are square, so when a case sticks in the chamber, the extractor’s hook isn’t held nearly as tightly around the rim. I’ve owned a bunch of long-extractor CRF bolt rifles over the decades, including 1903 Springfields, Model 54 and 70 Winchesters, Ruger 77 Mark II/Hawkeyes, and Montana 1999’s. All have square extractor slots and tongues, and on rare occasions the extractor’s hook has "jumped" the rim, leaving the case in the chamber.

This can also happen on 98 Mausers, but rarely, and usually with worn old military rifles. The only such under-beveled CRF extractor I’ve encountered in a non-Mauser is on my .416 Rigby CZ 550 Magnum. CZ manufactured quality 98 Mauser actions for decades, so was well aware of this small but essential reason the extractor worked so well, especially for dangerous-game rifles. So yes, there is some justification for believing the long 98 Mauser extractor is the ultimate controlled-round-feed design.


He's a major reason so many dangerous-game hunters prefer CRF bolt-actions, in particular those with Mauser 98 style extractors

Well that was a mighty fine, and unexpected morning read with my coffee!

Good explanation, thank you John.
It seems CRF is a bit over blown as far as DG is concerned with the more stable powders we have now mitigating the over pressure extraction issues but it still helps with short stroking which is a good thing when DG are encountered.

Cool article. Thanks JB!

And if the case is really stuck the extractor will rip the rim off of the brass case without ant problem.

Good read John.

Blacktailer,

Yep, less heat-sensitive powders have made a BIG difference over the last century-plus!

Have seen a few double-loadings with CRF rifles, caused by short-stroking. The one I remember most was during shooting at a simulated charging-buffalo target in Texas, and the guy short-stroked a Kimber .308 Winchester! However, the prize for winning the contest was a Tanzanian safari, so there was some pressure to shoot VERY quickly....

And I keep learning... Thanks