6.5x300 WSM

[Bob243]

Hello,

I was doing some research on different wildcats in a 6.5mm caliber and I ran across someone making reamers for this cartridge.. I think this may be a pretty hot round, and and looking for info on putting one together... Anyone have any ballistic info on this round? or any other info than the little bit I found?

Reasons I am interested in this ( suggestions, input, constructive criticisom is welcome )

1. I like the 6.5mm, I think it may be a great long range bullet
2. I like the idea of the 6mmBR and 7mmBR, the WSM seems similar in a sense that it is a short fat case, bonus being a magnum cartrige.
3. short action magnum

If this is as good as I hope it will be, I would put together something similar to the 700 VSSF or Sendero..
26" SS heavy barrel, probably with a break
find a cheap donor rifle with a good 700 short action
I have a very good gunsmith locally to do the machine work
(Chamber, mill the bolt face and use a SAKO extractor, machine a brake ect..ect..ect.. )

Please give me some thoughts...

Thanks,
Bob

[Mike Irwin]

Probably be about the same thing as the .264 Win. Mag. performance wise.

Overbore as hell and loud as hell.

The .264 just never impressed me all that much. I always felt that given the kind of game for which the .264 is suited, the .25-06 would be an equally acceptable choice. You give up some velocity, around 200 fps for most bullets, a little range, perhaps, but burn a lot less powder, and you don't get the magnum recoil.

[Bob243]

I am not quite shure what overbore is, can you explain this...

Thanks,
Bob

[Gewehr98]

But it still is a bit overbore, as Mike stated. The 6.5-06 and 6.5-284 are about the optimum case/bore ratio before you get that diminishing return effect on powder vs. velocity gain. With a good stainless barrel, moly bullets, and keeping the gun cool between shots, you can offset some of the throat erosion.

But there's an excellent selection of target and hunting bullets in the .264 caliber. Where the 6.5mm really shines is long range target work, using bullets from 140-155gr weights gives you a projectile with a beautiful BC that maintains supersonic velocity out through 1000 yards, hence the 6.5-284 USMC tests, the 6.5-308 of G. David Tubb, dare I mention what the Swedish Mauser in 6.5x55 is capable of?

I popped an armadillo in the brown eye (sphincter) once at 300 yards with my 6.5-06. The load was a 120gr Nosler Ballistic Tip, Moly-coated, running just a hair over 3200fps when chronographed 10 feet from the muzzle. Unbelievably thorough, imagine an empty baked potato skin with one end blown out...

[Gewehr98]

You have lots of "boiler room", meaning case capacity, to fill up with powder, in the effort to get more velocity for a given bullet/bore diameter. But you get into a zone of diminishing returns for the additional "boiler room" capacity.

There's an efficiency curve, where each grain of additional powder gives a corresponding increase in muzzle velocity for the selected bullet.

"Efficient" rounds maintain that curve, then they just plain run out of case capacity for any more powder for additional velocity.

Here's an example: The 7mm-08 is considered to be an "efficient" round, by virtue of it's ideal case volume and bore ratio. It gets good velocity for the amount of powder burned.

The 7mm STW is considered to be an "overbore" round, using the same yardstick. Sure, it can squirt out a 7mm bullet at velocities unheard of from the 7mm-08, but it does so at a cost or two. Namely, LOTS more powder burned, and rapid barrel wear as compared to more efficient cartridges.

The above examples are two extremes of the scale. P.O. Ackley was really big on case efficiency, and had a rather elegant way of describing when one was entering the realm of "overbore". If adding more powder behind a given bullet didn't produce a proportional rise in velocity, you had gone from efficient to overbore.

Look at the 7mm Remington Magnum, and then the 7mm STW. The 7mm STW has more case capacity for powder, and it does indeed produce more velocity than the 7mm Remington Magnum. But the velocity increase isn't proportional to the extra grains of powder used to get that increase.

Where overbore really starts to manifest itself is in barrel wear. An old gunsmith explained barrel life to me in terms even I could understand:

Barrel life is a function of how many pounds of powder you send through it, period.

Think about that one. A cartridge of a given caliber that tools along using an efficient round, say a 7mm-08, with only 40 grains of a given powder, will outlast another 7mm barrel, this time chambered in an overbore 7mm STW, that will use over 80 grains of powder to zip a 7mm bullet on it's way. Either way, the barrel is only going to last for X number of pounds of powder. How you "dispense" those pounds of powder through the bore is what determines barrel life. Here's the math, a pound of powder is 7000 grains. Divide that 7000 grains by 40 grains to see how many rounds of 7mm-08 you will shoot per pound of powder. Now take that same 7000 grains of powder, divide by 80 grains for the 7mm STW, and you'll notice that you get fewer rounds per pound of powder, and each round definitely sends more powder down the barrel than it's more efficient 7mm-08 cousin. Rephrased - Over the life of a given barrel, you'll end up sending more pounds of powder down an overbore caliber barrel than you will one that's an efficient caliber if you plan on shooting the same number of rounds.

You can have a barrel in 6.5x55 Swedish Mauser outlive the owner, but a .264 Winchester Magnum may not last you more than 2000 rounds.

[Bob243]

So the benefits of this would be Supersonic over 1000 yards?

Downfall would be its a a barrel burner?



How about accuracy?

What would a starting load be for something like this?

[Mike Irwin]

Supersonic at 1000 yards?

Maybe. A lot would depend on the type of bullet used. You'd have a better chance at maintaining supersonic velocity if you use some of the very low drag bullets that are out there.

Accuracy wise, in my experience, the overbore magnums just don't come up to the same level of accuracy that the quieter, more polite rounds do.

That could, however, be due to a number of things, including being overbore, or the simple fact that those stupid belts on a lot of magnum cartridges just are NOT as easy to get high accuracy results.

Some of the new beltless magnums are taking that fact into consideration, and it's about time.

Beltless cases are a lot easier to reload, easier to get consistent accuracy results with, and usually a lot less expensive because they can be reloaded more often (generally) and they are generally cheaper to manufacture.

Gew is correct that there are some really great bullets out in 6.5 mm. There are also a lot of very good choices in 7mm, so don't discount the 7mm Magnum.

Of all of the commonly used Magnum rounds, I really think the 7mm is the most versatile for someone who wants a 1-gun battery that will handle everything from mid-sized game up to big stuff.

It has the trajectory for decent long-range shots (I know a number of antelope hunters who use the 7mm in the west), too.

If there is a beltless version of it available, I'd say give it a hard look.

[Marshall]

I have a 6.5 remington magnum model 700 in short action. It to is a short fat case. I really like the caliber and enjoy shooting it. However, as a reloader I am constantly frustrated by the restriction on bullets I can use caused by the short magazine. The 6.5 likes long bullets. When I get over 120grs I have to seat them very deep in the case restricting powder space. As I recall the 300WSM uses the same length case(2.170). I think I would consider useing a standard length magazine or going to a .264WM. The .264WM will allow the use of 160gr bullets. And with less than max charges barrel life won't suffer. And, you know, for that matter if you handload the 6.5x55 you can get near magnum velocities. Just some thoughts I've had along the way.
Marshall

[Marshall]

I'd like to recant what I said about the.264WM. I think if I had it to do over I would opt for the 6.5-06. I don't believe you need magnum case capacity to make the 6.5 bullet a real zinger. I definately would stay away from the short action in 6.5 caliber.
Marshall

[xraymongral]

Remingtons new short magnum would be perfect as a 6.5. Its case is shorter then the WSM case, which reduces the need to seat long bullets deep, and has a very slightly smaller case capacity, which would probably keep it out of the "over bore" class. Lets keep our fingers crossed that Remington is smart enough to produce a .260RSM.

[Mike Irwin]

Well, given Remington's track record for introducing cartridges over the last 40 years or so, I wouldn't be holding my breath.

They seem to usually be a day late and/or a dollar short quite often.

The .244/6mm is a great example. Had Remington handled that cartridge correctly from the beginning, and introduced it as a general purpose round instead of a dedicated varmint round, I really think it would have blown the .243 Winchester out of the water popularity wise.

8mm Remington Mag.?

As Elmer Keith said about it at its introduction...

"What the hell good is it?"

.350 Rem. Mag.?

Another cartridge that could have been very popular if handled correctly. Unfortunatly it wasn't, so now it isn't.

Oh yeah, let's not even talk about the 5mm Remington Rimfire Magnum.

[xraymongral]

Right on the money Mike. I am hopefull that someone starts making reamers for a 6.5 based on the short Remington, then I will have to bite the bullet and splurge on getting a wildcat rifle.

[Mike Irwin]

Xray,

Certainly no reason why you can't have the reamers made for you.

[Bob243]

Thanks for all the sugestions........

I like the idea of the 260RSM that would be something to look at.....

Is the Rem USM out yet? I haven't really saan anything about it yet.


Marshall; Origionally I wanted a 6.5 Rem. mag, however I couldn't find brass except occasionally on e-bay, I have one box left from when my father has his Rem600 in a 6.5 ( I wish I had that )

Thanks,
Bob

[xraymongral]

Bob, this months Shooting Times has a article about the Remington short magnums. They are being produced in 7mm and 300. Based on a cut down Ultra Mag case, the 300's case is the same length as the .308's at 2.015", and the 7mm is 2.035" long. Loaded to a overall length of 2.825, with the tested factory rounds running a bit shorter then that. Case caacity of the 300 is 20% less then the 300 winchester Magnum, while being rated at the same velocity for the 180gr bullet. The 7mm has 12% less capacity then the 7mm Rem Mag, and is supposed to meet or exceed velocities of the bigger cartridge with the same bullets. So thats the gun rags take on it, have to wait and see what reality brings us.

None of my local stores have guns or ammunition yet, I can only imagine that Remington would have them in the store very soon to get in on the deer season gun buying.

[Steven Mace]

Even looking at the Remington website today you wouldn't know their short magnum cartridges even exist. Seems odd they were highlighted in a popular gun magazine yet the companies own website fails to make one mention of them. I would think Remington would be pushing their rifles & ammunition in these new calibers in an attempt to compete with the similar Winchester developments. Just my thoughts.

Steve Mace

[Mike Irwin]

Steve,

Exactly what I'm talking about.

Remington has a bad history of not publicizing their own cartridges very well even when they do handle them correctly.

Remington's last big hit cartridge-wise was the .25-06, and that already had a strong wildcat following.

Remington had to get their fingers in, though, and change the neck angle from the most common wildcat version, which soured a large group of people on factory rifles and ammo immediately.

[Marshall]

Remington ran off a batch of 6.5RM brass this spring. I bought 200. Probably should have bought more. Graff & Son is still listing them.
Marshall