That is a pretty warm load. I would start over at some where around 45 grains and work your way back up. A Handi should be able to handle full power loads, but every gun is different, even one #1 to the next #1 can be different. Throat lengths may be different between the #1 and a Handi causing case capacity issues and/or pressure spikes (or lack of pressure spikes) because of the distance to the lands. You need to basically start over with load development simply because it is a different gun, not because it is a Handi. just my 2 cents