jimranger4 Posted January 1, 2006 Report Share Posted January 1, 2006 Hey All, I am looking at putting together a model 93 in 257 Roberts. With the recent removal of the "+P" designation by many of the ammo makers I am concerned that I may run into a pressure problem down the road. The PSI is in the area of 54000 and the 6.5x55 and 7x57 top out at 51000. Comments? Jim Happy 06 Link to comment Share on other sites More sharing options...
Clark Posted January 1, 2006 Report Share Posted January 1, 2006 257 Roberts 45,000 cup 54,000 psi 257 Roberts +P 50,000 cup proof pressure 1.3 to 1.4 Link to comment Share on other sites More sharing options...
MorgansBoss Posted January 2, 2006 Report Share Posted January 2, 2006 This is an issue I have given considerable thought to as well - both 257Roberts AND 7x57. As Ned Roberts' cartridge used the 7x57 case and more or less equaled its pressures, AND the M93's were originally chambered in this round, all would seem well. However we are also cautioned to keep M93's below roughly 45000 CUP, which as Clark stated, equates generally to around 54000PSI. We do see pressure listings for both of these cartridges above this level though. Whats more many sources list the 257 at slightly higher pressures than the 7x57 OR vice-versa. Then the critical factor of handloading comes into play where pressures are dependant on the data used and the user's adherence to same... Are M93's safe with either of these cartridges? Given a sound rifle and factory or conservative hand loads, I think so. However we must always consider who may end up with the rifle in the unforeseeable future and their knowledge and prudence. To that end I would suggest considerable caution in making absolutely sure the rifle is in top drawer condition and as always, be sure to obviously mark caliber designation. Link to comment Share on other sites More sharing options...
z1r Posted January 2, 2006 Report Share Posted January 2, 2006 Here I think is how you can build a .257 on a small ring and still sleep at night with regards to the possibility that someone else may eventually end up with the rifle: Build it and use factory loads. None of the factory loads exceed about 45,000 cup except the +P's which go t about 47,500 cup. Any handloader that exceeds 45,000 cup is doing so at their own risk whether it is a 98 or a pre-98 action. The 95 action in good shape can handle these loads with ease as far as strength. The real issue as has been pointed out countless times before is that of the pre-98's inferior gas handling abilities should a case let go. Link to comment Share on other sites More sharing options...
Doble Troble Posted January 2, 2006 Report Share Posted January 2, 2006 Happy new year, Z! It's nice to have you back dispensing good sense. Link to comment Share on other sites More sharing options...
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