Rebated rim cartridges for precision

[fseaman]

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.

The "Google is your friend" part of your reply is seems churlish and condescending. Is that what you intended?

My "joined" date is misleading. I was here long ago and for a long time. I stepped away in 2019 to relocate to a new state and care for my then 84yo mother, now 89yo. All things are good there so I can get back to doing something I love.

Perhaps you missed the intention of the thread, which is to share real experiences about rebated rims. Not Shiraz's unless he chimes in, yeah, I know who he is. Not my first rodeo. It is your experiences as a rebated cartridge shooter. Not "overall general consensus is rebated rims don't handle pressure well" as that is something not true.

I can go to my real books library and trace updates going back for the 30 years I've had them. I can google cartridge specs and did.

I am not a 284 specialist in any way. As I said, I've have one 284 and it's a M88 lever gun. My loads conforming to the original specification. I have never experienced any of the "feared" rebated rim "problems". Absolutely no "don't handle pressure well".

There is one portion of your postulation that seems to have support which is that the original 284 was rated for ~56k psi. That is not "weak" unless there is failure at or below that pressure. If you are indicating that the 1963 pressure was less than you would like 50 years later and therefore "rebated rims don't handle pressure well", sure, I can see that logic but I would need to review 1963 and older pressure specifications to see if it is a "reasonable" position.

I have never found any of the 404 Jeffery cartridges to be "weak". Using my pressure sensor system, I know pressure much more accurately than "reading brass". Is it as accurate as OEM/Manufacturer/SAMMI systems. No and don't go there.

All belted magnums are rebated rims (well as far as I have found) so there is another strike against "overall general consensus is rebated rims don't handle pressure well".

I respect your work with the 284 variants so please share about that.

 

[Beluebow]

Your reply is q

Not following?

 

[MagnumManiac]

Been doing this a long time using rebated, belted and normal case head designs. The ONLY time I have seen an issue with a rebated rim had nothing to do with the case, it was with the action, how it fed and why it was doing it.
Firstly, going from a standard case, to a rebated FATTER case causes 2 things, the rails will grab the case causing the case to miss the extractor or to pop out in the wrong place and lay on the follower. (CRF actions)
Secondly, the LENGTH of the rails width must match the case.
The WSM rounds will need messaging of the rails when using a long action CRF rifle to convert, push feed not so much.
Timing is everything regarding feeding correctly, which is why many designs use a block in the magazine box so the case leaves at the correct point in bolt stroke.

Anyway, it's not the fault of the rebated rim, it's timing issues.

Never heard of rebated rims not handling pressure.

Cheers.

 

[Beluebow]

Here Alex Wheeler discusses the 284 rebated rim and pressure. Take from it what you will.

https://forum.accurateshooter.com/t...0-with-h4831sc-without-ejector-marks.3928455/

 

[fseaman]

Been doing this a long time using rebated, belted and normal case head designs. The ONLY time I have seen an issue with a rebated rim had nothing to do with the case, it was with the action, how it fed and why it was doing it.
Firstly, going from a standard case, to a rebated FATTER case causes 2 things, the rails will grab the case causing the case to miss the extractor or to pop out in the wrong place and lay on the follower. (CRF actions)
Secondly, the LENGTH of the rails width must match the case.
The WSM rounds will need messaging of the rails when using a long action CRF rifle to convert, push feed not so much.
Timing is everything regarding feeding correctly, which is why many designs use a block in the magazine box so the case leaves at the correct point in bolt stroke.

Anyway, it's not the fault of the rebated rim, it's timing issues.

Never heard of rebated rims not handling pressure.

Cheers.

Perfect.

This is the in spirit of the OP. Thank you.

Yes, when I built my 338-26 Nosler right after the 26 Nosler was finalized I experienced this. It was probably easier for me starting from a Weatherby Mark V 9 lug. All the things mentioned are easy to obtain.

 

[Beluebow]

The "Google is your friend" part of your reply is seems churlish and condescending. Is that what you intended?

The Google part isn't meant to be anything other than do a little work on your part. I found the Accurate Shooter thread within 30sec of searching. Sorry if I hurt your feelings. Certainly wasn't my intentions.

I posted a link for you anyway because I knew you wouldn't be happy with my reply. Hoping maybe you would take some insight from one of the top gunsmiths in the country.

Perhaps you missed the intention of the thread, which is to share real experiences about rebated rims. Not Shiraz's unless he chimes in, yeah, I know who he is. Not my first rodeo. It is your experiences as a rebated cartridge shooter. Not "overall general consensus is rebated rims don't handle pressure well" as that is something not true.

Having shot about 50K rounds of 284 it is my consensus and many others that the rebated rim of the 284 doesn't take pressure well.

 

[bigngreen]

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?

I didn't catch this earlier but belted mags are not rebated. .532 at rim and belt then .513 in front of the belt.

 

[fseaman]

Here Alex Wheeler discusses the 284 rebated rim and pressure. Take from it what you will.

https://forum.accurateshooter.com/t...0-with-h4831sc-without-ejector-marks.3928455/

I only played F-Class once before life changed. Now it's changing back but I was and I am more an ELR Ladder type game. When my I ran ELR matches, our qualifying was 5 rounds to first hit steel at more than 1 mile. Then we ran "closest" to bull, then moved out 500 at a time until no one hit or we ran out of time. I did have a competitor qualify with a 6.5-284. When I started running the same game from 600 to 1360 that same 6.5-284 competitor faired much better. I think I was using a Savage F-Class 308 as built for those. The 6.5-284 beat me often.

In the referenced thread, the OP admits to exceeding psi specification. It's not the rebated rim that is the problem.

You seem to be touching on why people have experienced problems with the 284 variants. Exceeding specifications. Prematurely aging brass. Risking blowouts.

From the reference thread: Alex Wheeler 6/13/2017 "I would want to know when you start to get heavy bolt lift. Its normally very close to where you get extractor marks. .284 brass with it rebated rim seems to show pressure signs earlier. Also, sharp edges around the ejector hole can show early sign. I use bolt lift as my main pressure indicator."

He is not saying it's weak. Is that what you are referring to?

Weatherby's new RPM line based on the 284 stretched to specifies 65k psi. I would be interested to see if you experience the same "issues" if you switched to 6.5 Weatherby RPM.

 

[fseaman]

The Google part isn't meant to be anything other than do a little work on your part. I found the Accurate Shooter thread within 30sec of searching. Sorry if I hurt your feelings. Certainly wasn't my intentions.

I posted a link for you anyway because I knew you wouldn't be happy with my reply. Hoping maybe you would take some insight from one of the top gunsmiths in the country.




Having shot about 50K rounds of 284 it is my consensus and many others that the rebated rim of the 284 doesn't take pressure well.

Not sure you know when to quit.

I'm too old to have "hurt feelings" but I know when someone is messing up a thread.

 

[fseaman]

I didn't catch this earlier but belted mags are not rebated. .532 at rim and belt then .513 in front of the belt.

Rim to belt was clearly stated. This is how threads get derailed. This is how our previous discussions diverged.

 

[Coyote Shadow Tracker]

When we were deciding to build a "F" Class rifle and pick a cartridge we went with the 6.5 x 284. We know a lot of people shooting "F" class and they shoot the 284!
Wish Lapua would start manufacturing the 6.5 X 284 again. Try buying or just finding Lapua now $$$$$$

 

[fseaman]

Having shot about 50K rounds of 284 it is my consensus and many others that the rebated rim of the 284 doesn't take pressure well.

The correct terminology is "experience" not "consensus" but we can go on useless side tracks as much as you want.

You said rebated rims but now it's the 284 and you are correct but side step the original reason, it was never intended for 65k PSI like a other cartridges.

I respect you experience. I have fired much more than 50k rounds but not of one parent case. I predict you wont' have read this part before continuing to provide stupid replies.

 

[fseaman]

When we were deciding to build a "F" Class rifle and pick a cartridge we went with the 6.5 x 284. We know a lot of people shooting "F" class and they shoot the 284!

And 284 based chamberings are quite successful in "F" class.

That is not the original purpose of the thread. It is a discussion of the pros and cons of rebated rims.

So far the pros are the increased capacity and surface area. Pedantic waring: PSI is a portion of the pressure formula. How many SI does the cartridge have? That is surface area in inches.

Cons so far have been bolt drag. That is a new one for me and really really gets to why I postulated the question and the "weak" 284 cartridges but that perceived weakness being applied to all rebated cartridges is how we get a little digging deeper into perceptions are reality. Until they aren't.

 

[bigngreen]

Rim to belt was clearly stated. This is how threads get derailed. This is how our previous discussions diverged.

Ya, you brought it up in this thread, maybe I'm not tracking what your saying but since it seems to be me causing derailment I'll just move on!