6mm(.243) or .243 Windchester
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In 1955, Winchester introduced the .243 Winchester cartridge, a necked down offspring of the 308 Win.......offered in their Model 70 Featherweight rifle......About the same time, Remington introduced their 244 Remington in the plain jane Remington 722 bolt action.....the cartridge is loosely based on the 257 Roberts/7mm Mauser style of case.....Winchester rifles had a 1 in 10 twist....the Remington had a 1-12 twist.....The word got out that the Remington 722 would not stabilize spitzer bullets over 90 grains in weight....while the sleek little Model 70 from the big red W had no problem with 100 grain bullets......Bad press hurt the 244 Remington and the 243 Winchester became a huge success and still is.....
Remington later changed the name to 6mm Remington and gave it a 1-9 twist which would stablize 100 grain bullets used for deer....
The 6mm Rem holds a grain or two more powder than the .243 Win......but both are in the same power/game taking class....which is varmints to deer.......The 243 is the rifle of choice for many beginners and recoil shy shooters/hunters....
Remington later changed the name to 6mm Remington and gave it a 1-9 twist which would stablize 100 grain bullets used for deer....
The 6mm Rem holds a grain or two more powder than the .243 Win......but both are in the same power/game taking class....which is varmints to deer.......The 243 is the rifle of choice for many beginners and recoil shy shooters/hunters....
when the 6mm rem. came out, lots of comparisons were made, and the 6 was declared the winner by a nose. since then the .243 has killed it in the market place. safe money is on the 243 for most shooters. Unless you really like to have something different.
6mm should be utilized in a medium length reciever(ie Birmingham Small Arms rifles) not a short action such as a Rem 700. The medium length action will allow you to seat the slug further out so you can get maximum velocities out of your handloads.
The brass will end up short, though. 6mm Rem is the better round, but only if you handload. And yes, I own and use both. - dan
You cannot chamber a 243 in a 6mm chamber unless the 6mm chamber is very sloppy.
Reason being the 243 case is larger in diameter at the shoulder than is the 6mm case at that depth.
I have always been a 6mm Remington fan, but I do own both. [3-6mm's, 1-243]
Always felt that the 6mm was more of a reloader's cartridge, whereas the 243 for the factory fodder user.
This is mostly due to the more limited choices in the 6mm permutation.
The practical difference in similar firearms is not a lot [100-150 fps advantage to the 6mm with a 100 grain bullet]
Regards, Dave.
Reason being the 243 case is larger in diameter at the shoulder than is the 6mm case at that depth.
I have always been a 6mm Remington fan, but I do own both. [3-6mm's, 1-243]
Always felt that the 6mm was more of a reloader's cartridge, whereas the 243 for the factory fodder user.
This is mostly due to the more limited choices in the 6mm permutation.
The practical difference in similar firearms is not a lot [100-150 fps advantage to the 6mm with a 100 grain bullet]
Regards, Dave.
You can NOT shoot a 243 in a Rem 6MM. the Rem 6MM is 1.725 long at the shoulder. The 243 is 1.560 long at the shoulder. The two are not the same cartridge. The 6MM is from the 257 Roberts catridge necked down. The 243 is from the 308 necked down. they are not intercangable ever. A very dangerous situation
oh.......it fits and I can shoot it........in a Remington Mohawk none the less........and my #### hasn't fallen off yet...........
243 is loaded to lower pressure, and the shorter neck just means the bullet has to jump a long way to the rifling.....maybe its the weatherby type lead that makes it safe in my rifle.........
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The fact you have done it does not make it a smart thing to do. My advice to anyone would be do not try to fire .243 cartridges in a 6mm Rem. chamber. And no matter how many times you have got away with it, it is not "safe" to do so.
Yodave's post is another example of how bad the advice can be on the internet.
You would have to set the barrel back in the receiver several threads, since the 6mmBR is much shorter than is the 243.
If you had sufficient barrel "shank" length, then it would be possible.
Otherwise, a new barrel may be needed. Boltface is fine.
Feeding from the magazine could be an issue, though.
Regards, Dave.
