Rebated Rims

[Roadkill2228]

So I've heard and read in many places that cartridges with rebated rims (such as .284 Winchester, the wsms, the Remington ultra mags, the new nosler cartridges, the .50 Beowulf, and the .50ae pistol round) are automatically a poor choice for a rifle intended for life and death situations (esp dangerous game hunting/protection). This is because it is held that because of the rebated rim the bolt is more likely to slip over the cartridge rather than grab it in when used quickly and roughly. My question is...has this ever actually happened to any of you who shoot such cartridges? Or anyone you know? Or anyone you read an article from? Because I have never heard of this actually happening and was wondering if it's a purely theoretical design issue or a real one. Same goes for rimmed cartridges in box magazines...supposed to be less trustworthy...but I've used some old .303 Brits and you couldn't make the things malfunction if you tried. Have at it!

 

[Roadkill2228]

Might as well throw in another reliability question...any of you ever experience difficult feeding with the wsm, rsaum, or wssm cartridges. It kind of seemed when the introduced them that the gunwriters determined before hand that they would feed poorly based on theory not field use. Any real life experience or feedback about short fat cartridge feeding would be welcome on this thread.

 

[BumbleBug]

Interesting post. I never thought much about reliability issues with rebated rims. I have shot a friend's .50 Beowulf in an AR some & it has never missed a lick for him or me.

BTW: I'm still trying to figure out why a control-feed rather than a push-feed bolt is a must for a dangerous game rifle(?)

 

[4thPoint]

Dangerous game....
You might not put down the game with the first shot. If that happens you may be scrambling up a tree, dodging out of the way, advancing rapidly to the rear, swinging the rifle to keep sights on track, on treacherous ground, etc, etc. A controlled feed uses mechanical interaction with the rim to keep the cartridge under control while loading. Push feed uses gravity.

Which one do you want to depend on keeping the new cartridge in place when the rifle may be in motion whilst the bolt is operated?

 

[James K]

Regardless of the type of extractor, I see no difference between a normal "rimless" rim (.308, 8x57) and a rebated rim. Feeding and extraction should work the same way.

The purpose of rebated rims is to allow a change to a larger diameter cartridge without changing the face or diameter of the bolt/breechblock. Strictly a convenience for the rifle manufacturer.

FWIW, the original concern with push feed was not about being chased up a tree by a lion; it was about leaving an unfired cartridge in the chamber and pushing the bullet point of the next round into its primer, with interesting results.

Jim

 

[Jim Watson]

The .425 Westley Richards is a heavily rebated safari cartridge.
It is reported to not be as trouble free as you would wish a dangerous game rifle.

 

[Gunplummer]

How about semi-rimmed? Just joking. I would say it depends on the action. Shotguns come to mind. A single, double, pump, semi-auto all work well. A bolt action box feed can be very finicky. I never messed with lever shotguns-don't know. Just food for thought.

 

[44 AMP]

I go with Jim on this one. The boltface & extractor don't "care" about the body size of the case. All that matters to them is the size of the case head/rim and the area of it the extractor grips.

When it comes to function, and malfunction, the gun's action design matters more than the rim to body ratio of the cartridge case.

As mentioned, the rebated rim design simply allows a maker to "shoehorn" a larger than standard case body into an action without having to change the size of the boltface.

ALL styles of rim work fine in guns built for them, and loaded correctly. Rimless and rebated rim cases have the least potential for feeding problems in box magazines, but we have well over a century of rimmed cases working through every action design and feed system, so clearly its not the case rim alone if there are issues.

Some say rimmed rounds don't work in box magazines, an obvious falsehood. Some say rimmed rounds don't work as well in box magazines, which is closer to the truth, but still not quite there. Don't Work as well in some magazines is even better.

Rimmed cases impose different restrictions on magazine and action designs not faced with rimless (rebated is functionally rimless), but nothing that has not been overcome long, long ago.

Yes, rimlock is possible (box mag) but that is nearly always operator error, or a flaw in the execution of the design. (worn/defective)

The only rebated rim round I have personal experience with is a friend's .50 Beowulf, which to date is several hundred rounds of flawless function. The round LOOKS funky, but seems to work fine. I did tease him when he first got it, that the recoil of the .50 would give him an "auto-collapsing" buttstock, but so far, that hasn't happened, and doesn't look like it will.

 

[hounddogman]

I have a winchester model 88 chambered in 284 never a problem ejecting or feeding

 

[T. O'Heir]

You're not trying hard enough if you can't get an Enfield to quit working. Usually the mag lips. snicker.
Anyway, rebated rim cartridges don't fail any more than any other cartridge. If one does, it's not the design of the cartridge.

 

[old roper]

I shoot 284 on long action and I've never had a problem with it feeding. Ruger, Browning and Mel Forbes made bolt action rifles using 284 case.

 

[SHR970]

any of you ever experience difficult feeding with the wsm, rsaum, or wssm cartridges. It kind of seemed when the introduced them that the gunwriters determined before hand that they would feed poorly based on theory not field use.

The writers based their assumtion on cases that are fat for caliber shorter length cartridges w/ steep shoulder angles.

My experience is based on one gun I have. It's a First Gen. Rem 700 ADL AWR from the custom shop in 375 RUM. It is a rebated rim, fat, long cartridge w/ a steep shoulder. It is a very light for caliber rifle that kicks worse than a clydesdale. In the limited number of rounds I've fired through it (860), it has yet to fail to feed or extract. That said, I am not that fond of the Reminton extractor used on their bolt guns but so far it works. A Mauser type is less likely to fail. Would I take this gun to go for the Big 5? YES I would.

 

[James K]

Rebated rims go back a bit. The first one I know of was the .276 Enfield, which dates to around 1912 and was the cartridge for the Pattern 1913 Enfield rifle, ancestor of the better-known Pattern 1914 (P-14) and U.S. Model 1917 (and the reason the magazines in the M1917 will accept six .30-'06 cartridges).

Jim

 

[Magnum Wheel Man]

the only issue I've heard with rebated rims stems from the 50 Beowulf, in which the case can set back as there is more push on a heavy load than the less material of the rebated rim can handle... I've not heard of any feed or extraction issues specifically related to rebated rims...

BTW... I have a custom Marlin lever action that started out as a 44 Magnum, that is now chambered in 50 A.E. ... never had an extraction issue with that gun, even though I often run heavy cast bullets through it...

 

[Mike Irwin]

The .425 Wesley Richards has the .276 beaten by about 4 years.

 

[jmr40]

An oldish thread, but I'll comment.

any of you ever experience difficult feeding with the wsm, rsaum, or wssm cartridges.

I don't think any of the WSSM's have ever fed as reliably as most would like. I've never owned one, but I read about more issues with these than anything else. Some of the very early WSM's had some issues, but manufacturers figured out that some minor tweaking of things like feed lips, feed ramps etc solved the problems. I've never known of a problem with them feeding once the problems were solved. My model 70 in 300 WSM has always fed just fine. No experience with the Remington short magnums. By all accounts the Ruger Compact magnum rounds worked fine in their guns. I don't think they were ever offered by anyone else.

BTW: I'm still trying to figure out why a control-feed rather than a push-feed bolt is a must for a dangerous game rifle(?)

FWIW, the original concern with push feed was not about being chased up a tree by a lion; it was about leaving an unfired cartridge in the chamber and pushing the bullet point of the next round into its primer, with interesting results.

This is one reason, but not the most significant in my opinion. With PF once a round is in the chamber the only way to get it out is to completely close the bolt, then open it and eject the round. The fear was/is that an excited hunter would partially chamber a round, then try to chamber a 2nd round creating a bad jam and useless rifle, and possibly a chain fire. With CRF the rim is grabbed shortly after leaving the magazine. If the shooter screws up that round will be ejected when the bolt is pulled back and a fresh round can be picked up and chambered into an empty chamber.

That is great in theory, but I'm not aware of it ever actually happening to anyone.

The name "controlled round FEEDING" is misleading. A PF rifle will feed equally well and maybe more reliably. The design is simpler and works at least as well FEEDING rounds into the chamber. A CRF rifles real advantage is a much more rugged and reliable EXTRACTION and EJECTION system. Even in the original scenario it is more reliable ejection that prevented a problem, not feeding.

For a rifle used in harsh, dirty conditions where it might see more abuse and have to be used dirty a CRF rifle is much more likely to function. It doesn't take much dirt, dust, mud, snow, or ice to prevent a PF rifle from ejecting or extracting. That isn't a problem hunting whitetails in the back yard. But for a guy spending 2 weeks in the wilderness of Alaska hunting out of a boat around lots of mud and in bad weather a CRF rifle offers a bit of extra security. Especially hunting something that could kill you. Or in the dusty, dirty African bush. Todays African hunters hunt during the day and stay in comfortable settings each night. 100 years ago when CRF was in its hey day an African Safari meant weeks in the bush in harsh dirty conditions.

 

[std7mag]

Hmmm, interesting....

I don't think there would be an issue as long as the cartridge were coming up from the magazine correctly.

I have both push feed, and "control feed" rifles. Have never dropped a cartridge from either one...

As for the push feed dropping out, usually the cartridge is started into the chamber, by the time the rim is getting past the lips on the magazine. Don't see really how your gonna start chucking cartridges into the weeds that way...

 

[mapsjanhere]

I think the stories of poor performing rebated rim cartridges are due to people modifying guns without taking the shape of the new cartridge into account. A well designed extractor shouldn't see a difference if the bolt face matches. An extra beefy one might jut be pushed out the extra 10/1000 and give you still decent overlap in normal operation - but not when you're hurrying it.