There was a thread about this, but I can't find it anymore.

For all your new Model 70 owners with the 7x57mm, how does it do with 174 gr bullets?

I'm pretty sure the new mod. 70 will shoot factory 175 gr. ammo as both Win and Rem make only that round..

I think what your remembering is That any custom 7x57 should be cut with a throat long enough to seat bullets out to a 30-06 length magazine. The will allow you seat the bullets out and get considerably more velocity..The Brno mod. 21 and 22 are prime example of this..and with the use of H414 powder and working your loads to max you can duplicate the .280 Rem very easily..You have, in effect, made a 7 mm Ackley out of your 7x57 by giving it roughly 5% or so more powder space. All my 7x57 are such..Surprisingly they all shoot 130 to 175 gr. bullets with their 1x9 twist, and the bullet jump of the 130 has no negative effect as claimed by some and I have used the 130 in many 7x57s with long throats.