Winchester load is WST, 22 grains, AASL wad, Winchester 209 primer. Right from their guide powder reloading book and repeated on the Hodgdon data center. But I find 1350 a bit fast for most of my regular shooting and reduce velocity down towards 1200 fps. Some have a need for speed and with international targets I understand, why but for regular clays or even small birds 1100-1200fps works for me. And I shudder at the new 1400+ fps mania that seems to be in every hunting load lately.
Fellow was shooting 12 gauge slugs that were 1500 fps and complained about the recoil. Duh, I thought. You are shooting them out of an Ithaca 37 with a slug barrel. Maybe six pounds to six and a half. Kills on both ends. Faster in most cases, does not make up for not very good. Having perfected my own flinch 40 years ago, with big rifles, I declined to try it.
One thing shell makers have to consider and accommodate is their ammo has to work a wide variety of semi autos, which may not be well maintained. So they must generate 8,000+ psi as the low end and not exceed 11,500. How many loads do they discard under 8,000 or 7,000 because they would be unreliable for those autos. Those are the very loads we mostly want but our 5-10% market share is not enough to generate a profit for them to exploit.
