[Terry_P]

The books show a pretty tight starting and max. I'd use 21.5 gr and a LPP.

 

[Terry_P]

Presumably the people that know have pressure tested the compressed charges and they are safe. Like any reload what's good for them may not be good for you so start low and work up. I have loaded compressed charges in rifle loads before and went slowly without problems although I do remember pulling bullets on my 222 Remington once because the load was showing pressure signs and they were compressed whereas others weren't a problem for the 222.

 

[Terry_P]

I would try a little stronger crimp before I went to a mag primer. If you had a good firm crimp and you aren't at or near max then you can step up to a mag primer just watch them for pressure as they will sometimes spike with a hot primer. If you are using a Ruger then they will take it.

 

[Terry_P]

It's a Hodgdon powder and their web site lists loads for Universal and for Clays. I am pretty certain Universal Clays is known as Universal and there are many loads for that powder.

http://www.hodgdon.com/shotpist.html