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The 6.5 Weatherby RPM cartridge design seems really odd.

The 6.5 Weatherby RPM cartridge design seems really odd.
« on: April 21, 2022, 10:02:54 PM »
Weatherby decided they wanted a high performance 6.5 cartridge that could run through their smaller 6 lug action, but that action is .375 H&H length, not 30'06 length.  So what was the point in designing a cartridge that is really too short for the action?  Why not take the 284 Winchester case, at 308 length, and stretch it all the way out to .375 H&H length and stuff that into the 6 lug action?

Too much case capacity?  Weatherby didn't think it was too much when they trotted out the 6.5-300, so that can't be it.

That just leaves the door wide open for Remington, Winchester, Nosler, Savage, etc to come in over the top of them with a longer version and leave Weatherby in the dust.

Tony Rumore



« Last Edit: June 02, 2022, 08:56:20 PM by TonyRumore »

Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #1 on: April 24, 2022, 07:35:39 PM »
I don't think anyone will offer a longer version, if someone wants more speed, they can get a 26 Nosler or 6.5x300Wea.
The RPM is within a very few grains of the 264WM, what's not to like. I like the round & I would likely already own one if the brass was better. Right now I thinking more about a 6.5x284 26" tube for my Rem 700 and if the RPM takes off good enough for quality brass to be made by someone then I can rechamber that barrel.
As far as the action length, Rem uses a mag action for their 270, 30-06, etc. has never bothered me and I am thinking about a MKV in RPM as my "light" rifle. I can always get it throated to seat the 156 Berger waaay out there!

Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #2 on: April 24, 2022, 08:25:22 PM »
We took the 284 case design and stretched is as far as we could (past the 30-06 length) and still have it fit and feed.  Feeding is one of the primary things that limits the length from being any longer.  Honestly, we couldn't design a case with any larger case capacity whatsoever that would fit and feed in that 6 lug action. My engineers had to do quite a few tricks to get that RPM to feed properly. The RPM is truly the absolute max for the 6 lug!

The cool thing is that we are able to get "magnum" performance in that action.  The 6.5 RPM is the fastest that you could possibly get in a sub 5 lb rifle and now the 338 RPM (near 338 Win mag velocities) is the same for its respective class.

Adam 

Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #3 on: April 24, 2022, 09:58:44 PM »
We took the 284 case design and stretched is as far as we could (past the 30-06 length) and still have it fit and feed.  Feeding is one of the primary things that limits the length from being any longer.  Honestly, we couldn't design a case with any larger case capacity whatsoever that would fit and feed in that 6 lug action. My engineers had to do quite a few tricks to get that RPM to feed properly. The RPM is truly the absolute max for the 6 lug!

The cool thing is that we are able to get "magnum" performance in that action.  The 6.5 RPM is the fastest that you could possibly get in a sub 5 lb rifle and now the 338 RPM (near 338 Win mag velocities) is the same for its respective class.

Adam

I think I just found out what the next Weatherby caliber will be, or am I just slow.

Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #4 on: April 25, 2022, 05:13:24 AM »
We took the 284 case design and stretched is as far as we could (past the 30-06 length) and still have it fit and feed.  Feeding is one of the primary things that limits the length from being any longer.  Honestly, we couldn't design a case with any larger case capacity whatsoever that would fit and feed in that 6 lug action. My engineers had to do quite a few tricks to get that RPM to feed properly. The RPM is truly the absolute max for the 6 lug!

The cool thing is that we are able to get "magnum" performance in that action.  The 6.5 RPM is the fastest that you could possibly get in a sub 5 lb rifle and now the 338 RPM (near 338 Win mag velocities) is the same for its respective class.

Adam

I think I just found out what the next Weatherby caliber will be, or am I just slow.

Just a bit slow, it was mentioned here a couple of months ago!

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Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #5 on: April 25, 2022, 06:36:54 AM »
I like the RPM case design, for hunting rifles. Not a fan of the short fan cases, unless your a match shooter.
Had the 6.5-284, in a Savage rifle, early version of the long range hunter. It shoot great, but just did not feed while. Also have one in a Savage bench rest rifle, single shot, great rifle and cartridge
Mike

Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #6 on: April 25, 2022, 05:27:26 PM »
Near .338 Win ballistics in a light weight rifle would be a boon to back pack hunters but a bruiser on the bench. As I get older I no longer walk five or more miles into the back country but if that rifle were available 35 or 40 years ago, I'd have bought one in a heartbeat.

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Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #7 on: April 25, 2022, 07:17:15 PM »
After getting my hands on some ammo and rifle i really like the round. My wifes camilla is a thumper will prob push me over the edge and own a deluxe, like I need another 6.5 by why not?? ;)

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Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #8 on: April 25, 2022, 09:10:20 PM »
After getting my hands on some ammo and rifle i really like the round. My wifes camilla is a thumper will prob push me over the edge and own a deluxe, like I need another 6.5 by why not?? ;)



I too think it will be my next purchase. But I'm going the other direction, away from my beloved wood. I am going to get it chambered in their Ti  action with fantastic plastic stock. It was designed to go in a sub 5 pound rifle so that's what I'm going to get.
Aussie gun nut.

Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #9 on: May 03, 2022, 08:20:23 PM »
As far as the action length, Rem uses a mag action for their 270, 30-06, etc. has never bothered me.

Well, it has always bothered me, and I actually did something about it.  I bought a Sako AIII in 280 Ackley when I was 18 years old and 40 years later, I stretched the 280AI to 375 length and machined a new new barrel for it.  It has no feeding issues stretched out, full length.

Standard 280AI on the right, 280AI Long on the Left.  To my knowledge, there has never been an '06 diameter case stretched to 375 length.  The 240 Gibbs, Catbird, SSK, and all the other super sixes, six-fives, etc that use an '06 diameter case are all too short for their actions......except this one.

It would be interesting to compare the case capacity of this stretched '06 case to the RPM case.  I'll bet they're pretty similar. 

Tony Rumore





« Last Edit: June 02, 2022, 08:56:41 PM by TonyRumore »

Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #10 on: May 04, 2022, 07:01:01 AM »
I bet the capacity of the stretched '06 and RPM would be similar too, which means to me there would be no point to it for me at least. But I used to have fun playing with such things.

Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #11 on: May 15, 2022, 05:58:50 PM »
I own a 6.5 RPM and have used it on whitetails and pigs. I love it. But, Adam Weatherby, you don’t get to state, “… the 338 RPM (near 338 Win mag velocities) is the same for its respective class.” Without a single rifle or cartridge available yet, the .338 RPM isn’t in ANY class. Every currently available cartridge is better than one that only exists on paper.

Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #12 on: May 16, 2022, 03:44:36 AM »
Other than holding the .30-06 diameter, I’m not sure what you gained over other options by increasing to a .375 length cartridge?

It wouldn’t be any faster than a 7mm Ultra Mag or 7mm STW?

Was this an exercise to see if it could be done?
JK

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Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #13 on: May 17, 2022, 01:11:00 PM »
Other than holding the .30-06 diameter, I’m not sure what you gained over other options by increasing to a .375 length cartridge?

It wouldn’t be any faster than a 7mm Ultra Mag or 7mm STW?

Was this an exercise to see if it could be done?







It's a specialty cartridge designed for a sub 5lb rifle capable of near magnum power levels.

The only thing it has in common with the 30-06 is the head diameter.The case diameter is a lot fatter and doesn't hardly have any taper.Case capacity towers over the 06.

Everyone that bought a 338-06 in the Weatherby Ultralite Mark V will surely have to own a 338RPM in a CarbonMark.
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Re: The 6.5 Weatherby RPM cartridge design seems really odd.
« Reply #14 on: May 17, 2022, 05:47:50 PM »
Other than holding the .30-06 diameter, I’m not sure what you gained over other options by increasing to a .375 length cartridge?

It wouldn’t be any faster than a 7mm Ultra Mag or 7mm STW?

Was this an exercise to see if it could be done?

I agree, it won't out run the larger diameter cases, but it never made any sense to me, to have something like a Remington 700 in 30'06, 270, etc, when the action is long enough to run a 375 length case.  Most guys that already have a 700 in an '06 length chambering, don't have the means to open up the bolt face, change the rails, etc to move up to a larger diameter case.  But they can certainly run a longer .473" case and leave the rails and bolt face as-is, and in my experience, the longer case feeds great.

And I question Adam's response, that stretching the 6.5 RPM longer caused feeding problems.  That seems a bit fishy to me.  I'm thinking maybe they wanted to go with the Cool-Kid Creedmoor Crowd and run a short case so guys could shoot ridiculously long bullets dangling way off the neck.

Tony
 
« Last Edit: May 17, 2022, 05:53:10 PM by TonyRumore »