.243 vs .243AI vs 6mm etc?

[mattri]

Tried a search sorry if this has been beat to death.

What are the differences in the various .243/6mm rounds?

Obviously accuracy improvements etc. but what do you gain from going from one to the other?

If you are shooting a .243 Win what do you gain by going to an AI or other?

Everything is a trade off, what do you lose?

Just trying to get an overall picture. Any suggestions or links appreciated, Matt.

 

[Steve Blair]

The .243AI and 6mm have similar capacities and performance. The .stock .243 is a little slower. I have three 6mm Remingtons. The improved .243 probably has good case life and is somewhat hard on barrels like the 6mm. In practical terms, any of the three would be a good choice. There are more than a few forum members that like the 6mmAI. I prefer a long action for 6mm with heavy bullets but a short action works fine for varmint weights.

 

[mattri]

Thanks for the good information. So at what point does it pay off to go to one of the other rounds from a .243? Where do you already need to be accuracy wise to see an improvement?

 

[Steve Blair]

All are accurate cartridges and probably do not have any practical advantage over another. The .243 and .243AI do have the advantage of Lapua brass. I use Winchester brass for 6mm.

 

[jerrschmitt]

I like the 243 AI for the simple reason that the brass doesn't seem to stretch as much as the standard .243. That being said, I perfer the 6BR to all of them. Less powder, longer barrel life. Never had a prairie dog say, "Sure glad you didn't shoot me with a .243AI."

 

[oldroper]

As to "Everything is a trade off, what do you lose?" I don't think there is one you want to build a 243 that what your getting as to which one is best. That argument has been going on since I started reloading 45 yrs ago between the 243/6mm.

If your building one or the other accuracy shouldn't be an issue difference might be in barrels/gunsmiths. My Kreiger barrel 243 has never had laupa brass fired in it's chamber I did try some in my Hart barrel 243AI didn't shoot any better than the Win brass. I have two 6RemAI one is my antelope rifle other use on varmits along with the 243AI. I shot a 6Rem for alot of years good caliber I did take that action for the 243AI.

I solved that problem many years ago as to which one is best shoot them all and enjoy them