Ummmm, OK - someone is liable to disagree with a couple of points here but whenever I have used Winchester powders, especially the WW231 , I use standard pistol primers, be they for large or small pistol.
I understand that the use of magnum primers with small charges of faster burning powders may give you erratic burning, possible double detonations and poor accuracy. Backing off a fast burning powder charge to accomodate the use of a magnum primer might be a formula for trouble.
Winchester advises the use of magnum pistol primers with larger charges of slower burning powders and a heavy crimp to assure full or complete powder burning.
I would check out what Midsouth Shooters Supply, one of Graybeard's sponsors, might have available - they should carry standard primers in the size you want. HTH. Mikey.