Most of the articles I've seen over the years have indicated that H4895 and IMR4895 are the best powders for the .250Savage. I've found suprisingly, that IMR3031 works extreamly well from my .257Robert's (have two). It too, might be worth trying.
The Hornady 100gr Spt has been the best bullet in it's weight range from the various .25's I've loaded for. Even the 1/14" twist should stablilize it adequately. I've had it hold together on deer when shot from the .257WbyMag at 3,700fps. It still expands and penetrates even better when fired from the .257Roberts at 2,800fps.The interlok feature works as advertised. I've taken several of the biggest deer I've ever killed with it. Never recovered but one, and it was fired from the aforementioned .257wby. Recovered bullet weighed 67.5gr and had the classic mushroom. At lower velocities it penetrates deeper, and expands a little less.
From your .250Savage, it will noticealby out perform the .243 despite what loading manuals and ballistic charts will tell you. (BTDT). The Sierra's are equally accurate, but don't penetrate quite as deeply. I've recovered many more of them, but I do still like them very much, but prefer the heavier Sierra's from my faster twist barrels.
Again, don't be tempted to hot-rod it. Just enjoy it's mild manners on the back end, and real killer performance on the front end. Again, it dosen't take 3,000fps to kill a deer.
My experience with the 87 and 90gr bullets are that they are neither fish nor foul. For a lighter bullet, I prefer the 75gr Hornady HP. I put several through several deer one night back in the mid '80's on a deer depredation permit on an airport. Well placed they will do a good job. As good as any of the 85-90gr bullets I've used. However, the Nosler 85gr Ballistic Tip did well too.
You've got your work cut out finding a "bad" load for the .250Savage.
Like another poster mentioned, the H414 and similar "4350" speed powders do suprisingly well from the "little" case.
Good luck!
I've got a special place in my heart for the little Savage. The first investigation I worked as a Conservation Officer involved a turkey illegally shot from a vehicle, from a roadway, on posted property. When I located the spent case, a Winchester .250 Savage.... I told myself, I gotcha now! I knew it was a rare rifle that had fired that cartridge. Took 6 weeks to develope the case/investigaton, but ended up siezing on a warrant a Savage M99 Takedown that was engraved and was once owned by XXXX XXXX, and had been stolen in a burglary from the XXXX Farms lodge in South Ga. Gun was returned to the estate after case was settled. No info on who stole it, though........ Successful prosecution of the turkey shooter however..... The ammo was an ancient box of 87gr Winchester Silver Tip..... Suspects vehicle still contained the box of ammo, and gun was still loaded when search warrant was served and executed. Tidbits of info I've picked up over the years indicates that THAT rifle made a trip to africa and accounted for a lion !!! So, the little Savage .250 is kinda special to me......
