Rechamber 243 to 6mmAI

[Weezer]

Is it possible to rechamber a 243 to 6mm AI and get a larger powder capacity or would it be better to go 6x284. Any thoughts ?? Thanks for the help. Weezer

 

[elkaholic]

Is it possible to rechamber a 243 to 6mm AI and get a larger powder capacity or would it be better to go 6x284. Any thoughts ?? Thanks for the help. Weezer

Both are possible depending on which action you have. Magazine and bolt length would be the determining factors. The .284 would definitely give you the most velocity but also the most barrel burning!.....Rich

 

[B23]

What about 243ai since you most likely already have 243 brass and if not you can buy Lapua brass and 100-200 pieces of brass will out last the barrel. Also, in my opinion, a 243ai is a better fit for a short action than is a 6-284. My 6-284 is on a Rem 700 short action and if I had a magic wand I would turn it into a long action.

 

[J E Custom]

The 243 AI would be the easiest and would get you around 100+ ft/sec plus better brass life
with no changes to the action.

The 6mm WSSM would also be a lot more powerful but some action work and mag work
is nessary.

For more power and velocity you will need to go to something like the 6/284 or the 6mm/06
as long as you have a long action.

Just some of the choices.

J E CUSTOM

 

[Trickymissfit]

Both are possible depending on which action you have. Magazine and bolt length would be the determining factors. The .284 would definitely give you the most velocity but also the most barrel burning!.....Rich

You can't get a cleanup with a 6mm Remington reamer in a .243 chamber. I'd have bet the farm a couple years back, but you can't get there from here. But you can do a .375" shoulder setback, and get everything to cleanup. How I learned this is embarrassing. On the otherhand a 6mmAI reamer will clean up!
gary

 

[Trickymissfit]

What about 243ai since you most likely already have 243 brass and if not you can buy Lapua brass and 100-200 pieces of brass will out last the barrel. Also, in my opinion, a 243ai is a better fit for a short action than is a 6-284. My 6-284 is on a Rem 700 short action and if I had a magic wand I would turn it into a long action.

the real problem with a .243AI is case shrinkage during fire forming. The neck is already too short for good barrel life in the generic .243, and then you'll shorten it another .03" to further aid throat errosion. I'd suggest you look at doing a .243AI reamed short off a 6mm AI reamer. This gives you everything! The longer neck for better seating and barrel life. Cases are easilly formed from generic 6mm brass, or even .257 Roberts brass. Ford load data yousimply use .243AI data, but you end up with the better neck and shoulder angle.
gary