Winchester catalogs them loaded with #5 shot at 1300 fps.

https://winchester.com/Products/Ammunition/Shotshell/Long-Beard-XR?compare=%7B%22ids%22%3A%5B%22%23STLB125%22%5D%7D

No, I've never seen them for sale in stores. MidwayUSA carries them, but they aren't in stock. Put yourself on the waitlist for them and buy them the moment you get a notice. I don't think they are all that popular for the reason you stated. But if MidwayUSA gets some people on their waitlist, they'll request some from Winchester.

https://www.midwayusa.com/product/1018439972?pid=227786

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https://vcdl.org/