The mighty 6mm's: Winchester vs Remington

S

Spectre

Staff Alumnus
I plan on having a short barreled .244 built soon. The 6mm Remington (based on the 7x57mm) was the cartridge I had planned on having the piece chambered in.

The 6mm Rem has a bit more power than the .243, but I have begun to wonder if the .308-based case will be more efficient from barrels that are less than 18". Will the extra powder in the 6mm Rem case go unburnt if fired from a 17" barrel? Or, will the 6mm Rem still retain a power advantage that will be even more important from the very short barrel?

Thanks in advance for your input.

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Anyone else want to 'negotiate'?
 
Tough one. I have a 6mm Remington with a 20" barrel and it is fine without any sign of being overbore, though I don't load it too hot. I don't know about 17" though.

Jim
 
Pure speculation: Is it reasonable to look at the .244 as somewhat similar to the '06 and the .243 as somewhat similar to the .308 insofar as efficiency, or behavior as regards barrel length?

In the early days of the .308, I read that the concept was for the .308 to have '06 *military* velocity in around a 19" or 20" barrel. Case design plus Ball Powder was to achieve this--and, 53,000 psi vs. the '06's 47,000 psi.

Only if this is reasonably factual would I state that the .243 might, repeat might, be more efficient--comparatively--in a 17" barrel.

(How's that for weasel-wording? :) I should go into politics! :barf: )

Hmmm. Thought about a Bull Pup in .244 with a 24" barrel? The OAL would make for a great car/truck gun.

Art
 
Now, THAT's a terrific idea. Dunno how much more a BP would cost, though, and trigger pulls on bullpups tend to be "spongy".
 
In my experience, the .243 and other 6/6.5mm cartriidges with large case capacity perform best with barrels between 22 and 26 inches.
The terminal ballistics of the .243 are very dependant on velocity. Cutting the barrel so short will dramatically reduce the effective range of the weapon and put a bug in the accuracy equation.
It will also limit your powder selection quite a bit.

If you really want a short barreled 6 or 6.5mm rifle with anemic performance, save your self a bundle.
Go pick up a used, (never fired, dropped once) 6.5 Carcano.... ;)
 
Gee, MAD DOG, I sure am glad nobody told some 20 deer or several coyotes about that. :D Or insulted my lil 19"-barrelled toy, for that matter. :)

I do know that my pet load of 3031 and the 85-grain Sierra HPBT will spread coyote guts over half an acre, mas o menos. I told my buddy, "Shoot'im in the neck! Don't shoot him in the..." Kablooey! Guess where? Yup. (I dunno. Maybe 60, 70 yards.)

Spectre, a friend once took a Model 70, .220 Swift and bedded the action into a bullpup stock. The bedding is the hardest part of the deal, of course. I think the typically-spongy trigger setup can be dealt with via a thicker rod and more precise machining for the pivot-pins...His rig sure was easy to handle inside a car, though. We did lots of night time jackrabbit hunting, back then.

As usual,

Art
 
I bought a Remington 700ADL in 6mm Rem. when they first came out in 1964, and have been a fan of the cartridge and the rifle ever since. The rifle has a 20" barrel which was standard on all mid-calibers in the 700 at the time. It has fired only 39 rounds of factory loads, but many hundreds of my reloads, which are good for .75 to 1.00 moa any day, and on good days one half that.
All the smart money was on the .243 Win., because the rifles available for it during the first couple of years handled 100-gr. bullets better than the 6mm, and shooters perceived the Winchester gun and load as more versatile. My gun has the one in 9-inch twist that works well for everything from 60 to 105 grains. 'Autorities' claim that the 6mm is easier to handload than the .243, because of its longer neck. Other experts say that the short fat .243 case is inherently more accurate than the .6mm. They are both probably right.
For nearly 40 years, my Remington has been used on everything from varmints to big game and at ranges from 15 to over 400 yards. I use just two loads: the 85-gr. Sierra spitzer and the Nosler 100-gr. partition, with IMR 4350. I don't know what the velocity is for either load, but it kills what it hits, way out past Fort Mudge.
Maybe a .243 Model 70 would have done as well.
 
My vote: .243

I'll agree that the 6mm is superior in case capacity, however that advantage is minor. I'd rather have the superior load availability, brass availability, and market acceptance of the .243. In that class, I prefer the 6.5 Sweede and 250 Savage myself. These are superb calibers in their own right and only take a little away in terms of small varmit flexibility. I don't own the 6.5 or 250 as I already have the .243.
 
Glamdring, I think Mad Dog was referring to the fact that you get higher velocities from barrels out around 24"; this gives better terminal ballistics out beyond 200 or more yards. He didn't mention accuracy...

:), Art
 
In reply to Badger's comments:
A 'minor superiority' is what wins horse races.
I won't argue with anyone who prefers the .243, but I would point out that 'market acceptance' and even 'load and brass availability' should hardly be determinative criteria in selection of a cartridge. Anyone who is serious about shooting loads his own; brass and bullets for the 6mm are easy to get, and a hundred cases will last most of us a lifetime. As for 'market acceptance, whatever that means, I'm sure it doesn't mean 'hitting the mark'.
I like and shoot the 6.5 Swede. It's a good medium game cartridge that will do, with its long heavy bullet loads, for pretty big stuff (Swedish moose.) Not as good for a varmint/big game combo as the .243/6mm, in my view.
The .250 Savage is another nice mid-sized round. It's handicapped now only by the non-availability of good accurate rifles for the cartridge. Old Savage 99's and the occasional Ruger are about it; neither of those are famed tack-drivers.
A really neat little carbine can be made up in 6x45 or 6mmTC/U, on the Contender frame. It will serve the same role as the bigger Sixes, at a bit lower velocity. I'd not go after bears with one, but for chucks/fox/coyote, etc, it isn't a bad choice. A specialist/handloaders choice, of course.
 
Forget the ballistics for a moment. The .243 fits into a short action and the 6mm Remington doesn't.
Since you're building the rifle it only makes sense to use the short action for less weight, shorter bolt travel and (arguably), a stiffer receiver which (all things being equal), "should" equate to greater accuracy.

I don't think there's enough difference between the two cartridges to worry about accuracy or ballistic advantage, but surely the short action of the .243 is a something you can hang your hat on as a "plus".
 
Keith, while what you say about short actions is true, there are very few 'short' actions on the market that won't also take the 6mm. The new Savage model 10 is a notable exception and I'm sure there are others. Generally, short actions will handle the 6mm length cartridges. Other things you say about short actions are also true, but I don't think they rank that high in terms of accuracy as most do. I'd rather have a shorter, fatter cartridge than a shorter, stiffer cartridge. Both usually come with the territory.
 
Slab:

I'll agree that the .243 is inferior and that the factors I listed aren't important to a handloader. Let me submit, however, that if you're building a rifle without regard to factory chamberings, you should really look to wildcats or, at least, an improved case. The 6mm and .243 both can be improved significantly by blowing out taper and increasing shoulder angle.

Back to the original posting, he's building a short-barreled 6mm and asking which would be more efficient from a short barrel. Being a bit shorter and fatter, the Winchester case might get the nod here. Never owned a short .244, but my .243 788 Carbine is quite effective out of an 18" barrel. Haven't Chrony'd them, but muzzle blast is much more noticeable and accuracy is excellent.

Bottom line is that we are splitting hairs a bit. The 6mm will give you more velocity and is just as accurate. Given the fact that I already have dies and loads developed, I'd surely go for the .243 were I building a similar project. Make sure you pick the correct twist rate for the weight range you plan on using and don't look back.
 
Thanks, all.

I will be using a '91 Mauser action that should *just* fit the 6mm.

Based on responses here and other threads, I believe I may sacrifice a couple of inches of portability, and go with a slightly longer bl.

Thanks again.
 
I'd be mighty reluctant to build a 6mm OR a .243 on a Model 91 Mauser. The action is not made for the pressure levels that those cartridges generate. Why not consider a Model 98 for that work. The 6mm will feed just fine through a nice 1909 Argentine or VZ24.
 
I'll build the .250 AI at a future date, hopefully on a switch-bl .22-250.

I plan on using the extra mag width of the Mauser, especially since the 6mm Rem provides the EXACT amount of power I was looking for, with factory ammo.

The '91 was built for a cartridge a bit more powerful than the most powerful 7x57mm. Knowing that the 6mm Rem is based on the '57 case, and also knowing that it generates even less power than a 7x57, I don't see a problem. George agrees.

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You just shot an unarmed man!
Well, he should have armed himself when decorated his saloon with the body of my friend.
 
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