I have a high number 03 Springfield that was customized, that I got in 69 and re-barreled a couple of years ago, and a 03-A3 that I made into an 03-A4, with a Rem 2 groove barrel, and I have used 54 grains of 4350 with either 180 gr SRA spritzer boat tails, or 175 gr SMK. I have used both H4350...