Have any gunwriters used this one before? Any thoughts/comments on it?

It supposedly gets 3200+fps with 140 gr. bullets out of a 23.62" barrel.

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The 6.5 x 63 Messner Magnum

The 9.3 x 64 Brenneke case has functioned as the parent case for the 6.5 x 63 Messner Magnum, which's essentially a 6.5 mm (.264 in) necked-down version of the 9.3 x 64. The wildcat status of the 6.5 x 63 Messner Magnum ended in 2002 when it got C.I.P. certified and became an officially registered and sanctioned member of the German 64 mm "family" of magnum rifle cartridges.
The 6.5 x 63 Messner Magnum has 5.42 ml (83.5 grains) water cartridge case capacity. 6.5 x 63 Messner Magnum maximum C.I.P. cartridge dimensions. All sizes in millimetres (mm).
Americans would define the shoulder angle at alpha/2 = 29 degrees. The common rifling twist rate for this cartridge's 200 mm (1 in 7.87 in), 6 grooves, � lands = 6.45 mm, � grooves = 6.70 mm, land width = 3.50 mm and the primer type's large rifle magnum.
According to the official C.I.P. guidelines the 6.5 x 63 Messner Magnum case can handle up to 440 MPa (63,816 psi) piezo pressure.
The idea behind the 6.5 x 63 Messner Magnum was to develop a very powerful 6.5 mm long range hunting cartridge that achieves very high muzzle velocities out of relatively short 600 mm (23.62 in) long rifle barrels. The developer, Mr. Joseph Messner from France, chose the 9.3 x 64 Brenneke as parent case, since it offers enough case capacity and a competent gunsmith can relatively easy rechamber a standard Mauser 98 or any other bolt action rifle to accept 9.3 x 64 Brenneke based cartridges. Beside the 6.5 x 63 Messner Magnum rimless rifle cartridge Mr. Messner also designed a rimmed version for break action rifles of the cartridge called the 6.5 x 63 R Messner Magnum.

This cartridge has maybe a 1.5 grain advantage over the .264 win mag. Performance would have to be very close. What advantages would this round possess over the Win Mag?

I don't know; hence my question. The 6.5 x 63 Messner Magnum has 83.5 grains water capacity, is the water capacity of the 264 Win. Mag only 82 grains?

The other thing we know is that it doesn't have a belt

Published water capacity of the .264 Win Mag is 82 grains of water. From my understanding it takes about a 5% increase in case capacity to realize a 1% gain in velocity.

Just looked at my reloading notes. My average measured water capacity to the neck-shoulder junction for Win 264 WM cases is 84.1 grains. FWIW practically however, max charges I can get into a 264WM case with powders like H50BMG is 75 grains, with a long drop tube, loading 140 grain bullets to OAL 3.34".

Interesting cartridge, but nothing really new. Von Hoff, RWS, and the 7mm Sahrpe & Hart necked down as well as the 264 Winchester are pretty close to the same thing. All 61mm to 65mm. I really like the 6.5's will have to what is different about this one.

6.5x68 for comparison:

"Extremely thick brass results in 'only' 5.584 ml (86.0 grains) H2O cartridge case capacity for the 6.5 x 68"

http://www.tripatlas.com/6.5_x_68

I would ask the Jeff Cooper question: "What's it for?"

My 6.5-'06 is a 6.5X63, but built on a narrower case (same head size as the 9.3X62 or 9.3X66).

The .376 Steyr was also developed from the 9.3X64 case, here going from 9.3mm to 9.5mm and shortening the case from 64 to 60 mm.

There is some wildcat interest in the 6.5 on the wide, short case so short actions can be used. My current idea for a "fave" is a 6.5 RCM. I have not tried one of these, so my theory might not survive the reality test.

I like 6.5s too.

jim

I'm sure it works, but sounds pretty much like a whole bunch of other options that have at least some modicum of popularity. I can't see it taking off much.

With commercially available cartridges that do the same thing, why go through the pain of an obscure cartridge? If you wildcat a new cartridge, at least you get some satisfaction and fun. But an obscure cartridge is difficult to obtain nad just (generally) a PITA.

For my purposes with the rigs I shoot, if I wildcat in 6.5, I would use the 270WSM Norma brass and neck it down to 6.5, hence 6.5WSM.

Yup!!!

Any new news or updates on these European 6.5 magnums given the 6.5mm craze these days?

Weatherby’s 6.5 RPM is the way to go, here.

Components aren't widely available and isn't the rebated rim potentially problematic depending on field conditions and extractor type? I think you're spot on as to case capacity and being more available than the 6.5 x 63 Messner Magnum.

Canadian Lefty,

Aside from the microscopic loony examination of every tiny difference in various cartridges, why keep obsessing after more than a decade? Today there's a 6.5mm rifle cartridge for any obsession, whether tiny or huge, belted or beltless or rebated. Why not just pick one and be done with it?

You're right and I agree with you. I need to stick a fork in it. If I put a stake in the ground today, I'd get a 264 Win Mag. with a 25-26" barrel and be done. I just might ask a rifle maker to do that in the next few months.

My decade+ obsession with the 6.5mm caliber had been solved (all this time, at least) and for all practical purposes with the 270 Win. cartridge (or when needed/wanted, with my 300 Win Mag). I just keep revisiting and thinking the grass might be green enough on the 6.5mm side to justify another rifle in the Coues Deer, Pronghorn and Mule Deer class...Then, I'd just rebuild my 270 Win with a shorter 22" barrel (currently 24") and have a .264 Win Mag (or similar) with the same length barrel as my 300 Win Mag and have an all-round pair.

Math tells me that I should be shooting a little flatter and more importantly with slightly less wind drift, all else being equal if shooting, say a .264 Win Mag. vs my 270 Win, Plus, I can have a .264 Win Mag built to the same weight, just slightly longer, heavier barrel. The .264 (6.5mm) has some classic panache I do know that the .264 Win Mag won't do anything that I can't already do at least as well as my .300 Win Mag. so...back to square one or as Brad puts it, cartridges are more alike than different.

What is perplexing is that in reality? after having shot someone else's 264 Win Mag Model 70 at the range, it seems to have more bark than would appear on paper...maybe because I was shooting a right-handed rifle left-handed but...On paper, it would appear as though the 264 Win mag, even if handloaded to it's full potential ( (I removed a bunch of ballistic data for comparison here)) doesn't seem to gain much on the 270 Win other than maybe 1-2" less wind drift at 500 yards or if consistently shooting past 600 yards...yet it burns more powder, has a better B.C. bullet (comparing near equal sectional densities), all else being equal. I like your idea of a 6.5-.270 Improved or even a 6.5-280AI but would like having more velocity (to, at a min. better differentiate from a .270 Win) so I've been looking at alternatives between the 6.5-06 and the 26 Nosler (which looks great on paper but Norma discontinuing Brass and some describing how finicky it is to handload and get to shoot accurately?). I could also be convinced to go with a 270 Weatherby (another classic) or the new 27 Nosler...

If you think the .264 has more "bark," you probably wouldn't like the 26's bark (or the 6.5-.300 Weatherby's, since they get basically the same ballistics, with similar powder charges.)

I have only been around two 26 Nosler rifles, and neither was finicky: my Nosler Liberty model, and a friend's Browning X-Bolt. I'd had my Nosler rifle for several years, and any bullet in the 140-grain range shot VERY well with a maximum charge of US869. Lighter bullets shot well too, but don't remember the details, though could look them up.

My friend asked me about loading the 26, and I told him the above. He tried US869 with 140-grain Ballistic Tips, and the Browning shot little bitty groups. He used it last fall to take a big mule deer buck at around 450 yards.

CanadianLefty, you and I must be twins separated at birth... I sold my M38 Mauser more than 15 years ago and have been staring at my 6.5x55 dies ever since... For the last two months i have been pondering another Swede, or 260, or 6.5-284, or 6.5 PRC, or 26 Nosler, or 6.5-300 ... and for the last month looking hard at the 264 WinMag and twice had the bid ready to launch on Gunbroker... and didn't do it.

In the end I pulled the trigger on the Weatherby Weathermark in 6.5 RPM. I am looking forward to putting it through its paces.

My diagnosis: you havent yet settled on the cartridge waiting for you... it ain't a 270.

For math, run some numbers with the 127 LRX at 6.5 RPM velocities on Hornady's ballistic calculator, then play around with even slippier bullets. Ok, so the differences are small... we ain't in this for exercise. WE ARE splitting hairs and loving the nuanced gains provided by the 6.5...

Funny and thank you for your candor. Yes, I suspect that my 270 Win might take a backseat in the near future, not only to my 300 Win Mag, but to a sleeker .264 (~6.5mm) cartridge.