Safety of Rebarreled Steyr M95M 257 Bob

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Apr 27, 2013
I recently acquired a steyr m95m barreled action on gunbroker. It was listed as an unknown caliber so I caste the chamber and determined that has been nicely rebarreled to 257 roberts complete with bolt head modification. I have restocked the gun however before I go any further with finishing the build I was looking for some input on whether this action would be safe to fire modern 257 roberts +P ammo. Most off the shelf ammo for the bob is of the plus p variety and not many are loading it in the standard loading. Thanks in advance.
The M modification was intended to use all military loads for the 8x57JS, which would be around the 50K psi level. I doubt if the Roberts +p would go any higher than that, so safety-wise it should be OK. The real issue is extraction, which is going to depend on how smooth the chamber is and how hard the brass. That may be be deciding factor with these factory loads, and the only way to find out is to try them.

A word of warning: do not EVER load a round by dropping it in the chamber and closing the bolt on it! The clearance between the extractor and the bolt race is such that you may flex the head of the extractor and crack it at it's thinnest part. I know because I made just that mistake many years ago, and spare extractors were not available then, so probably even less so now. Always feed rounds from the magazine and you should have no problem.

Good luck!
.257 Roberts is rated 45,000 CUP which is LESS than the 7mm Mauser it is derived from and the same as .250 Savage used in Savage 99 lever actions.
.257 Roberts +P is rated 50,000 CUP, same as .30-06.

So if the Steyr was strong enough for European 8mm, it is strong enough for either flavor of Roberts.

There are a lot of stories about why the .257 is loaded so lightly, but I do not think they hold water.
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