Has anyone necked this case to 6.5 or smaller cal.

I was thinking 25 cal would be best

6mm White Oak Armory.

5.56mm White Oak Armory.

I put together an AR upper in a 6mm SPC but I haven't had time to shoot it yet, the brass is sized and ready to load but just haven't had time. First I've heard of a 6mm WOA, is there any info on it somewhere?

Awhile ago the guys over at The Reload Bench forums necked it down to 6.5. Called it 264 RLB.

The Reload Bench

Did we here at AR start the cart naming after the forum concept with the AR series of carts?
Here was the first I had seen, then I saw Campfire do it now RLB. Interesting.

As I said in a thread on the 25 SPC the SPC seems to shine with 85 to 110 grain bullets so a 6MM or 25 seems to be the best diameter IMHO and better for long range. the 6.8 seems to be best out to 300 yards for game but a 25 would make it good for another 100 for game and even further for target.

Here is a mock up of what a 257 SPC would look like flanked by a 6.8 and 223