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Clark · March 24, 2012, 04:09 AM

I have a 257RAI VZ24 26" barrel that will do 3900fps 75 gr... but the primer pockets get loose and the barrel will Copper foul quickly.

3500 fps is my speed limit for Moly coated bullets, and that also keeps my primer pockets tight.

The 6mmRem is SAAMI registered at 65,000 psi and the 8x57mm is SAAMI registered at 35,000 psi, but they both use the same kind of brass made with the same kind of tooling and are both going to get lose primer pockets at 70 ~ 72 kpsi in one shot and I will make hunting load at 67 kpsi. This is the 1889 7.65x53mm Mauser case head made with a large Boxer primer pocket.

The 257 Roberts is somewhere in between the two that are the same

The VZ24 will change the rifle geometry [read plastic deformation of bolt body and bolt abutments ]at 100 kpsi with the 300 H&H magnum case head. But that is much more bolt thrust than me working up to the threshold of long brass life for the Mauser case heads used in the Roberts.

March 24, 2012, 04:09 AM	#6
Clark Senior Member Join Date: December 4, 1999 Location: WA, the ever blue state Posts: 4,678	I have a 257RAI VZ24 26" barrel that will do 3900fps 75 gr... but the primer pockets get loose and the barrel will Copper foul quickly. 3500 fps is my speed limit for Moly coated bullets, and that also keeps my primer pockets tight. The 6mmRem is SAAMI registered at 65,000 psi and the 8x57mm is SAAMI registered at 35,000 psi, but they both use the same kind of brass made with the same kind of tooling and are both going to get lose primer pockets at 70 ~ 72 kpsi in one shot and I will make hunting load at 67 kpsi. This is the 1889 7.65x53mm Mauser case head made with a large Boxer primer pocket. The 257 Roberts is somewhere in between the two that are the same The VZ24 will change the rifle geometry [read plastic deformation of bolt body and bolt abutments ]at 100 kpsi with the 300 H&H magnum case head. But that is much more bolt thrust than me working up to the threshold of long brass life for the Mauser case heads used in the Roberts. __________________ The word 'forum" does not mean "not criticizing books." "Ad hominem fallacy" is not the same as point by point criticism of books. If you bought the book, and believe it all, it may FEEL like an ad hominem attack, but you might strive to accept other points of view may exist. Are we a nation of competing ideas, or a nation of forced conformity of thought?