Unfortunately, Winchester no longer makes them. How do I know, I reached out to them, because I'm in the same boat. Yep, checked all kinds of sights online, nothing. My old guns can't shoot TSS or this new stuff, and it won't shoot anything but 2 3/4' shells. Now, on another sight, I got lit up by some of these new ammo manufacturers saying that the new TSS shot never touches the barrel because of the new wads, blah, blah, blah ------ Yep, I'm not trusting that at all, sorry. I just know TSS is too hard on the older barrels, and I love running my old guns, not ruining them.
Just buy some Winchester XX or Federal Grand Slam and see which your gun likes the best. If you're trying to shoot 50-60 yards with 2 3/4, you might be best to stay with Winchester XX in #4's, that's a long ways for #5's. Now, if you're keeping it within 40 yards, you don't need longbeard XR anyway, a good XX or Federal #5 will be fine. Now, I have some buddies that swear by nickel plated shells, but they keep their shots very close, within 30 yards or so. Have one guy that only uses smokepole type gun, he's with 20 yards, lol. Crazy old coot.