Naki:

Your 9.5 is one I'd be careful with in regards to "under"-expanding bullets. It more or less duplicates the performance of my 9.3x57, and as I've used a number of resized .375 bullets in my 9.3's, is closer yet.

You might be interested in this post:

http://forums.gunboards.com/showthread.php?t=49260

I was quite surprised at the results of the 300 grain Hornady as it is one of the quicker-expanding bullets in the .375 H&H as demonstrated in my tests posted here elsewhere.

The good news is that very simple modifications can be made to bullets that will improve their opening up for the slower-moving rounds {or down-loaded H&H} as outlined in that post. Certainly there are bullets in .375 that would work well in your 9.5x57 that would require no modifications. But as demonstrated, even a bullet that fails to open properly can likely be made to do so with vey little effort.

I would NOT want to shoot a deer with that resized 300 Horny with an unmodified tip in my 9.3x57. It might open well, or might act just like a solid. With the tip modified as outlined, it ought to be a bomb on whitetails or elk.