Originally Posted by beretzs
Originally Posted by Riflehunter
I think because of the substantial difference between the shape of most current .257 bullets and any future high bc bullets, the throating would have to change on all the old SAAMI specs, otherwise the loaded cartridges will be running out of magazine length or alternatively running out of neck grip on the bullets because of the more radical boat-tails and pointy tips. So newly designed cartridge cases would be the way to get around this problem. This is the problem I faced, I couldn't get the throat right for both future .257 bullets and the current ones...so had to reluctantly go to 6mm.

I think the throat on the current guns might work fine. The higher BC deals have a longer nose and an ogive further back. Wouldn’t be surprised to see the standard throat work reasonably well. But it’d take some measuring with them. I don’t have any of the current ones on my shelf.
On the heavier high bc bullets, like the Hornady 134 grain, it would work if you currently have plenty of magazine length. My comment was more in relation to say a hypothetical high bc 100 grain bullet which would be much shorter than a 134 grain bullet and you would probably run out of grip, if needing to seat close to the lands to get good accuracy.