Re: 6,5x55AI Reloading
Norma MRP is simlar in burn rate to Vhitavori n-165 as is Reloader-22 (Alliant Powder) and H4831 (Hodgdon) Powder.
I'm thinking that you may want to consider Vhitavori N-160 which is a little faster and probablly would work very well with 120-140g bullets.
I'm actually in the process of building a 6.5-06 Ackley Improved and It is similar to your 6.5x55 AI with quite a bit more case capacity. I have to resort to the much slower powders like RL-25, IMR7828, Retumbo, ect....
Norma Powders are very hard to find where I'm at, so I haven't been able to use them. I use Hodgdon, IMR, Accurate Arms and I'll be trying Some of the Reloader powders as well. Vhitavori is some what available, but more expensive and not always in stock.