View Full Version : Rechambering advice

July 20, 2005, 04:44 AM
I am looking at buying a new rifle for a 6mmREM but can only get the model i'm after in a 243WIN. I don't understand the methods of rechambering, particuarly when feeding the catridge into the chamber. I know the barrel will have to be changed or worked on as the 6mmREM is a 0.244 diameter an not 0.243.

As the shells for both calibers are different, both in height and shoulder angles how does rechambering work? Is the action changed?....

It's most probably really easy to get a 6mmREM in the USA but in Australia..... its really hard. Most if not all 6mm varieties are 0.243WIN.

July 20, 2005, 06:09 AM
The 243Win, 224Rem,6mmRem and other 6mm rounds all use the same bullet and have the same bore dimensions. The 6mmRem is a longer case than the 243Win so you could just ream out the chamber .Rim and body diameter are the same and the receiver should be the same so it should feed OK.Is it worth the effort since you get only about 100 fps higher velocity ??

July 20, 2005, 08:55 AM
Maybe you can find an older model 600 in 6MM Rem. The action needs to be a LA for the 6mmRem to work the longer round out of the magwell with heavy bullets seat further out. I am going to build one very soon using an older receiver from a .270. The 6mm has a .188" longer case and the OAL is long enought to stub in the SA. It also uses a 26* shoulder. Good luck

Jim Watson
July 20, 2005, 09:32 AM
Mete is right and wrong. Both cartridges use the same .243" bullets, and the head diameter is the same so the bolt would not be changed. 6mm is a longer cartridge OAL and might or might not fit into and feed from the .243 magazine.

BUT a 6mm Remington reamer will not "clean up" a .243 Winchester chamber.

If the rifle of interest has a heavy barrel, it could be set back, rethreaded and rechambered. Otherwise the only route would be a new barrel, either on the .243 or on a "donor" action like Countryboy's. Either would be expensive and gain you only a little velocity. And you would have a rifle for an obsolescent cartridge with lower availability of ammunition and a lowered resale value.

Bad idea.

July 20, 2005, 06:30 PM
I agree with Jim that maybe it's not worth rechambering up from a 243 to a 6mmRem. I guess it was bad timing for remington when they released the 244 round as i feel it is better than the 243.

I wasn't sure how much work was going to be needed to rechamber this cartridge, so i guess i'm on the hunt for another round that is both versatile for varmint and medium game and has a flat trajectory and still maintains velocity above 3000 fps (muzzle). Energy needs to be around 1700 - 2000 ft/pound energy at 100yrds.

any recommendations?.....

dale taylor
July 20, 2005, 06:48 PM
Look for6.5x55 or 6.5 Magnum. Old Rem. 600 or 660 are also possibilities. [email protected]