Rechamber 6mmbr to 243,

[paulT]

I am in process of ordering a 6mmbr barrel with a 1 in 8 twist to shoot the 105 Lapua scenars and getting it rechamberd to 243, would rechambering it at minimum "match" chamber sammi spec be the way to go, ILL be mostly using the 105 scenars in lapua brass, also Lapua recomends their oal with the 105 to be 2.677in would reaming chamber with 0.020 jump to lands sound about right, thanks for your help, paul T.

 

[Aussie_bob]

I read this thread a couple of times and went away confused but decided to come back and have a go, first why would you order a barrel chambered in 6mmBR if you are going to re-chamber in .243?
Or am i reading this wrong.
Anyway blunder on.
Order your barrel blank unchambered get the cases you will be using and the projectiles seat a projectile to the base of the neck give this to your gunsmith along with the barrel and action and tell him you want .020" jump to the lands and that's what he will do if you find you want to be closer just have to not seat the projectile as deep.
If i have miss read your post i am sorry is early hrs of the morning this side of the pond. Most Smiths will advise you if they think it is wrong but if you have the brass you will be using and the projectiles they can do a chamber to suit.

 

[paulT]

Thanks for reply Aussie bob, i shoot a Blaser Lrs2 and interchange barrels between a 308 and a 243, my current 243 barrel is a 1 in 10 twist thus limiting bullets to 90grains, tried 105 scenars and they would not stabelise they need 1 in 8 with 24inch tube, Blaser only produce 243 with 1 in 10 twist and would be willing to rechamber the 6mmbr barrel that has a 1 in 8 twist to 243, since i already have competition dies and lots of Lapua brass and vit n165 i feel that with the 105 scenars and the ability to run them a bit faster in the 243 case it would be just as acurate and possibly a flatter shooting round at 1000y than the 6mmbr, thus i was trying to find out what were so called "match" minimum sammi chamber measurements for 243 as the work is going to be caried out in germany and i wanted to get info on best poss chamber measurements as well as any relevent reaming work before final barrel order,Regards Paul T, Ireland.

 

[Aussie_bob]

Thanks Paul i now see your dilemma having to do every thing at long range, in another country)maybe someone from up your end of the world will be able to help with the info you are looking for.
Cheers from Australia

 

[RickB]

In my experience a BR chamber will leave a ring if rechambered to any 08 based case without setting the barrel back which would require rather more work. Why won't the manufacturer simply take an 8 twist barrel before it is chambered for the BR and chamber it for a .243 Win?