My rifle is a C Sharps 1885 action with a Kreiger bbl. I was able to find some Al 300mp, and will try a couple more loades tomorrow. So far I've tried 4227, 4198, 4759, 2400, AA #9, and 1680 which has been the best - so far.  I even tried 5/unique that was recommended in an old Ideal Hand Book. Poor idea. I only have the Acc 125-m and Ideal 287202, both pb, and Saeco 071-7mm, with & without gc. I do have a 150 gr pb coming, someday, and am still hopeful.
I don't know if the picture will show, Ten-mile, it isn't the same bullet you have in mind, but you can easily read the dimensions, if that'll help
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Users/Gorge/Desktop/28-125M-D.png

Wasn't able to make it to the range over the weekend, but will get there tomorrow with the 28.
I've been shooting a 32-40 Cody Ballard, an original Rem #3  but chambered for the 8.15x46r, and CPA Stevens 44 1/2 in 32-20 CPA competitively for many years, all breechseaters. None of these guys gave me the amount of trouble the 28 has. Arthritis has made even those mild rounds uncomfortable, hence the 28. I have a 25-20 wcf bbl for the CPA, but it isn't competitive at 200, at least for me. I don't intend to give up on the the '85, but it sure is humbling.