What kind of pros and cons can you guys come up with on necking down a 7mm rem. mag case to take a 6mm/.243 bullet? I have thought about this a long time. It would be more cartridge than the .240wby. wouldn't it?

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It's better to have it,and not need it,than to need it,and not have it!!!!!!!!

The .240 Weatherby is basically a belted 30-06 case and has very similar case capacity.So yes its more than a .240 Weatherby.I'm sure it has been done before.It would be seriously overbored but thats what wildcatting is all about.

If only a 7mm could be beat, for starters!

.264, and .308

Pros: Brass is readily available and your gunsmith will love you because you'll be back for a new barrel in 1,500 rounds, max.

Cons: Stupid rim. You'll get a very marginal increase in velocity and I'm not sure there are many .243" bullets that would really benefit from it.

6mm-284 is a MUCH better platform to build a long-range target, varmint or even pronghorn/small deer rifle with.

P.S. Wildcatting is not about going overbore, it's about spending a ridiculous amount of money to get a marginal increase in performance. I love 'em!

purpledragon... probably the same reason there was 25 WSSM and not a 25 WSM.

There was an article in the Gun Digest a few years ago about the .244 H&H Magnum (as I think it was called), based on a necked down .300 H&H case. This was apparently an English commercial cartridge from the 50s??
Good discussion about its performance and barrel life, if you can find the article. This would be very similar to your proposed .243-7mm Magnum.

The 244 H &H is quite an old cartridge- I think it goes back to the 1920's, or even older. The original 244 H & H had the long tapered shoulder of the 300 H & H, not the sharper shoulder of the more modern 7mm Magnum.
In those days, powders weren't slow enough to benefit a large case/small bullet design like that, so the 244 H &H never was very popular. The 244 H&H also got the reputation of being hard on barrels, much like the 220 Swift did back in those days.

With the slower burning powders it would be pretty fast and flat shooting. I know your interested in a .243 caliber, but look up the .257 STW (Shooting Times Westerner) sometime. Its a screamer. It'll fire a 100 gr. bullet at almost 4000.

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I live in America. Why do I have to press 1 for English?

I think it would be silly with light bullets and that you wouldn't gain too much over the 243 win/6mm rem. However, with the heaviest bullets, a fast twist, and a long barrel I think you would see a difference. It would excel in the super long distance shooting. Much like the 22-250 Ackley Improved does with the heavy 70-90 grainers and a fast twist.

Ditch the 30 cals for starters, and reap the benefits. Wouldn't mind rolling 6.5

.308, that's funny!

Good article here by Layne Simpson on the pros and cons of 6mm-06, 6mm-284, and 240 W.

http://www.rifleshootermag.com/ammun...808/index.html

I am personally thinking of a 6mm-06 for my next build. Not too overbore and easily available 25-06 brass to work with.

Barstool(er)

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Beverage of Choice -- Jeremiah Weed
Weapon of Choice -- 30 Mike Mike Gatlin Gun

I bet .30 cal has killed more big game in north america than any other caliber.

If you only count the last 100 years or so, that is undoubtedly the case. Prior to the late 1800's, 30 caliber was used primarily for small game but that was at much lower velocity than we see with modern cartridges.

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Ask me about QDMA.

Hallelujah?? I'd rather be gunning .284, regardless of the pursuit.

Now for accuracy and ballistics over all, the 6.5 caliber is just very hard to beat down range period.

That is a roger on the 6.5, as I shoot Mr. Simpson's big 7, and he himself says he likes his big 6.5 better. I am seriously thinking of having a 6.5 STW built I already have the 7's cases to size down just a smidgen....

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It's better to have it,and not need it,than to need it,and not have it!!!!!!!!

I've got the 7 also. AWESOME round!!!

I've also got a Model 70 magnum boltface donor gun that I've been thinking 6.5 STW on. Also thinking .257 STW and .470 Capstick.

Decisions, decisions.

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"Too much gun always beats the alternative."
Elmer Keith

Purpledragon,

Ross Seyfred did something similar 20+ years ago by necking the 7mm Rem mag to 6mm and "improving" the case. It was called the 6mm mach V?. I cannot remember at this time. It is a real scorcher. You might be able to find the old article, it was in Guns and ammo or you may be able to get the data direct from him. Last I knew you could reach him at Elk Song Ranch. ( his home)

There were some interesting complications that arose in it's development, more specifically, trouble with producing very hard carbon deposits in the barrel due to the quantity of propellant being forced down a small bore. Things may be easier today with the newer powders.

Good luck
Todd

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