ignorance!

Today I went to the range to work up a load for my Saure 101 in 308 Win. I'm shooting 42.5 -44.5 in half grain increments of 8208xbr Win primers Win brass and 155gr Berger VLD hunting bullets. I had already done the length test and they shot the best at 2.820 and they like .100 jump.  So, I shot a ragged hole with 43.5gr and everything else was better than 1 inch at 100 yards. I have no velocity readings as my my magnetospeed took a dump! I would think somewhere around 2775 and that should suffice for the area I'm hunting. when I got back home I was looking at old notes and noticed that all my best groups were way under max loads for any powder bullet combo that i've shot. Most of the time it's at least 2gr under published max loads. I'm not looking for speed but it makes me wonder how I can reload for my shooting buddy and i cant get enough powder in the case but im getting ejector marks at 1.5 under max? The rifle shoots great maybe it just doesn't like powder.