Rebated rim cartridges for precision

fseaman · Sunday at 11:14 AM

Many xxx Cartridge vs yyy Cartridge build threads end up going off the rails with people chiming on regarding belted chamberings and rebated rim chamberings.

This thread is intended to be specific on why or why not rebated rim.

The list of cartridge designs that have succeeded with rebated rim is very long indeed.

I have been using rebated rim designs for 20 years. Mostly bolt action with one lever action.

I have never understood the "anti" rebated rim position. Anyone with "anti" rebated rim, could you explain the source. Engineering, application, field use issues.

bigngreen · Sunday at 11:29 AM

Feeding from a stagger feed mag and tuning that cycle to be perfect at all speeds is way smoother than a rebated rim, that's pretty much it for me.
It's not an anti rebated rim it's just why even have a minor compromise these days.

eshell · Sunday at 11:29 AM

The 6.5-284 has been extremely successful for long range competitions since the'90s and it has a rebated rim.

I have one F-Class rifle in 6.5-284 now, and had a second 'tactical' style rifle that I burned up one barrel with and replaced with a second 6.5-284 barrel. Both rifles shot under 1/2 MOA with no feeding problems.

I never paid any attention to the rebated rim and it never seemed to cause issues. I do not understand how it might negatively affect precision.

fseaman · Sunday at 11:31 AM

I'll start with my view an experience with rebated rim chamberings.

Basic: rebated rim designs were created for the purpose of increasing case capacity for length and to match existing bolt face standards.

I have used only 2 parent cartridge types, the 284 Winchester based and the 404 Jeffery based.

I have a Winchester model 88 lever action in 284 Winchester. This box magazine, lever action to me is handy and fast. I have used it for hunting though never with success as these were my "home" hunts and were I lived at the time the weather was often 100 degrees so deer were never to find. My use at the range to develop the load and try factory loads was always flawless.

I have approximately 10 404 Jeffery based cartridge WSM, Nosler and RUM. I have used the for hunting, LR and ELR precision games.

I have never had a magazine feed issue.

fseaman · Sunday at 11:34 AM

bigngreen said:
Feeding from a stagger feed mag and tuning that cycle to be perfect at all speeds is way smoother than a rebated rim, that's pretty much it for me.
It's not an anti rebated rim it's just why even have a minor compromise these days.

This is what I have heard from all the "anti" rebated rim guys.

Are you a gunsmith building custom actions?

In the other thread you mentioned 300 WM. All belted case designs are rebated rim to belt? Have you ever had the same issue with your 300 WM builds?

Beluebow · Sunday at 11:50 AM

The 6.5x284 and the 284/variants were the gold standards in Fclass for many years. The overall general consensus is rebated rims don't handle pressure well.

bigngreen · Sunday at 12:08 PM

Again, not anti rebate, have dozens of rebated rim reamers!
I've tuned hundred of rifle to feed as a gunsmith, if I stand in front of my reamer draw and am building a 30 cal magnum I'm making the decision on the smallest things, yet it might be a rebate or a belt, or maybe a shoulder angle that day, we are littlerly at that point. If I'm mag feeding I don't like bolt drag and the case moving anything more than it needs, rebated rim all day long, very minor deal, not an anti position in any way shape of form!!

fseaman · Sunday at 12:26 PM

Beluebow said:
The 6.5x284 and the 284/variants were the gold standards in Fclass for many years. The overall general consensus is rebated rims don't handle pressure well.

I have never read that anywhere. Please post links.

fseaman · Sunday at 12:42 PM

bigngreen said:
Again, not anti rebate, have dozens of rebated rim reamers!
I've tuned hundred of rifle to feed as a gunsmith, if I stand in front of my reamer draw and am building a 30 cal magnum I'm making the decision on the smallest things, yet it might be a rebate or a belt, or maybe a shoulder angle that day, we are littlerly at that point. If I'm mag feeding I don't like bolt drag and the case moving anything more than it needs, rebated rim all day long, very minor deal, not an anti position in any way shape of form!!

I have been away for a bit, we have great had discussions in the past.

I know you aren't really "anti" rebated rim. I do understand the challenge of tuning the feed mechanism as I have done it a little.

Can you expand on "If I'm mag feeding I don't like bolt drag and case moving anything more than needs". What drags?

bigngreen · Sunday at 1:47 PM

fseaman said:
I have been away for a bit, we have great had discussions in the past.

I know you aren't really "anti" rebated rim. I do understand the challenge of tuning the feed mechanism as I have done it a little.

Can you expand on "If I'm mag feeding I don't like bolt drag and case moving anything more than needs". What drags?

The case is held up against the bolt when closed, I want the case to move as little as possible to be in the feeding position, and I want as little pressure on the bolt from the spring as possible. The more the rebate the more the case has to be into the raceway and more the spring travels with higher tention. If you have a fluted bolt you have less "feel" of that case too depending on the pattern, again we're talking mostly the most minor of things.

RichCoyle · Sunday at 1:53 PM

I am eighty years old and never heard of feeling the case.

bigngreen · Sunday at 2:27 PM

I've seen rifles that with a round down you can open the bolt and stand the gun upright and the bolt won't move, I like to be able to tip the gun back and the weight of the bolt will eject the case then tipping it forward and it strips from the mag with the minimal of help. It's little things no one would pay attention to!

fseaman · Sunday at 3:12 PM

bigngreen said:
...I like to be able to tip the gun back and the weight of the bolt will eject the case then tipping it forward and it strips from the mag with the minimal of help. It's little things no one would pay attention to!

That makes your goal of no drag from the bolt much more understandable.
And
I have tuned feeding enough that this part of your explanation, I understand and is reasonable.

I have never done a same rifle, bolt dragging vs. not dragging test but we have had enough discussion in the past that I know you have "been there, done that, got the t-shirt"

Beluebow · Sunday at 5:37 PM

fseaman said:
I have never read that anywhere. Please post links.

Google is your friend.......Having shot out 40ish barrels in 284/variants I have a decent opinion on a 284 rebated rimmed cartridge. Most of it has been Lapua brass with probably close to 3k pieces of the double headstamped Norma that Shiraz Balolia had special made. I'm definitely not anti-rebated rim.

Rebated rim cartridges for precision

fseaman

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bigngreen

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eshell

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fseaman

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fseaman

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Beluebow

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bigngreen

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fseaman

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