I may try 4350 as well. I have some of that. I have a case of Accurate MRP which loads the same as AA 3100. That may be a little slow for the Roberts but I have a bunch of it. It works good in 243 and 270 rifles as well. I think I have all of the current reloading manuals. I may try the swift 120 grain semi spitzer as well because of the short magazine box. I quess I could get the box altered to accept a little longer OCL.