Be very careful with that kind of thinking!After reading around a bit it seems that some manuals say to drop one full grain of powder when going from the long .87inch case(MK1) to the shorter (MKII) case. So it makes sense that if I have load data for the shorter case I can add one grain to the range given and load the longer case.
Make sense?
Be very careful with that kind of thinking!
I'd stick with the loads listed, regardless of the case size, considering that the factory MK2 loads have a muzzle velocity of 650 fps.
The Colt New Service is probably the only revolver that's strong enough to withstand hot .455 loads.
(many of the 455 Colt New Service revolvers had their cylinders reamed to accept 45 Colt)
Handloads.com has this to say.
http://www.handloads.com/loaddata/d...&Weight=All&type=Handgun&Order=Powder&Source=
Given the difference in the data, I'd definitely go 10% less powder to start then work my way up. KD
In a pinch it sounds like the .45 acp dies will work but the price and scarcity of the .455 brass is it really worth it. I will just buy the correct dies and be done with it.
My research has come up with 6grs blue dot but I have not tried that load yet myself.