Be certain to build your 9.5X57 cartridges as close as possible to the dimensions of original factory loads for smooth loading and function. I'd save five of the Kynoch rounds for reference (or find some DWM 531).

Though nothing is smoother than a properly fed Schönauer magazine, those prior to the M1924 can be rather particular regarding length and profile of cartridges and may jam if your projectiles are too short overall, seated too deeply, or too narrow near the top third.

Build them like this and they'll run through like melted butter:

Sadly, the Hornady 3715 projectile (.375 270 grain round nose), is no longer available. It fit the M1910 Schönauer magazine almost perfectly and was economical. If you run across any Hornady 3715 you'll probably want to buy them. Woodleigh has solids that are of correct size, weight, and profile at a higher cost. If you find another source for .375 270 grain round nose, do tell the rest of us!

Hornady 3715 (.375 - 270g RN), Original DWM 531.

Here's how DWM 531 was loaded in 1935:

Kynoch still does limited runs from time to time - very expensive. Quality Cartridge (U.S.) now manufactures fresh, properly headstamped brass for the 9.5X57 (.375 RNE) at a reasonable price.

Brass for the M1910 can also be easily formed from .35 Whelen. The Whelen has a higher shoulder than the 9.5X57, so the dies push it down to the proper location. Avoid using other _X57 brass to reform unless you're going to draw it straight first. Simply reforming _X57 brass in 9.5X57 dies will leave the shorter, narrower shoulders of the other X57 cartridges untouched.