To add to the discussion...
First of all, be
VERY careful about load data from the internet. You don't know me. I could be an anti-gun terrorist hoping to blow up all gun owners one overload at a time. I could be a 10 year old kid making this all up as I go along. You have no real way of knowing. OK, there's my disclaimer.
I have an Armi Sport (Chiappa) Spencer carbine in 56-50. I use a bullet from Accurate Molds, which can be viewed here:
http://www.accuratemolds.com/bullet_detail.php?bullet=51-350S-D.pngThat bullet feeds fairly well in my reproduction carbine, although I do get some hitches which I think may be somewhat inherent in the design or my technique.
From
MY carbine, using 8.0 grains of Unique, I chronographed a MV of 950 (the same that mgradio got with 8.5 grains from
HIS carbine). I didn't get that load from a book or any other approved source, so I'm taking all the weight of risk on my own head. If you try to mimic me, you take all of the risk too.
I have not done any serious accuracy testing with that load. My main targets are tin cans at 25 yards and it works just fine for that.
Good luck in your quest.
CC Griff