Browning Speed LR 300 RUM

[dbergy]

I saw that there was an older thread for this, but I want to try and get some more information. I have a Browning Speed Long Range chambered in 300 REMINGTON ULTRA MAG with a 1.8 twist and I am getting ok groups with it, but not great. I was wondering if someone had experience with the same rifle and what would be a good starting point for bullet brand and weight to reload with? Thanks.