My experience is limited to 44 mag and 45 colt, but H110 has performed better for me near max loads. However, as previously stated, check all screws, including on the ejector rod housing and head to the range.

Yes, we all have bad days at the range, but if you suspect that you are the problem here is what I do. Shoot 4 shot groups, so randomly load your cylinder with 4 live rounds and 2 empty brass. Spin your cylinder and close the gate without looking. Flinching etc will be exposed and this has helped me. I guess if you have a 5 shot go with 3 shot groups.

Finally, this is a long shot but several years ago I purchased a new SBH in 44 mag and I could not shoot it well. After much money and time wasted I figured out the barrel was screwed onto the frame crooked. Use a strait edge from both sides of the top strap to check this. Good luck.