I have already done most of what you suggested. The loads I shot wereI would strongly suggest starting at 38 and work your way up .5 grain at a time, given the problems you have already had. Measure the velocity of each load and analyse the fps gain for each .5 grains of powder added. If you get to a spot where the gain is less than half the extra fps of the previous load gains, or worse zero gain, stop.
40 grs at 2984 fps
40.5 at 3001 is +17 fps
41 at 3044 is +43 fps
41.5 at 3052 is + 8 fps
42 at 3087 is + 35 fps
42.5 at 3129 + 42 fps.
So is 41.5 max load for this rifle with these load components. H4350, CCI 400, 103 ELD-X and Alpha brass?