I know a guy using 700x in 28 gauge. [emoji51][emoji15] He says he found the load in some old manual. I don’t believe him.Titegroup is listed as #15 on the burn rate chart, you don't get down to 28ga appropriate powder until #30
The ONLY way titegroup would work in 28 gauge without destroying your gun is if someone were loading an EXTREMELY light load, like 1/2oz @ 1000fps, or something along those lines, with like 5 grains of powder, for some real esoteric requirement.