It's hard to get a good gunner armor that you would feel comfortable with and a good bow to match with but I got one combo for you. The Dragonwood shin armor is reliable with a good shogun ceantaur bow, especially with showroom model. Since it already has charge 4 you don't need the gunner helm, switch it with the blademaster helm. You now have the perfect armor for a gunner like yourself.
Skills-Paralysis Coat add(Good for Showroom model bow as it can't have this coating by itself)
Quick eating(Really useful to get out of a jam)
Hunger increase [Lo](Can be fixed with Fasting jewel)
This armor and weapon have 11 slots but 9 because you really don't want the hunger increase skill.
You can have any 2+ 1 slot gem skill and a couple 2 slot gems giving you reasonable skills. A common curiosity with gunners is the monster's health, sometimes gunners might get concerned with certain quests with bosses like diablos that is ready to be capture just after some time starting the quest, and still will take some time to finish off, so I recommand the Tranquilizing Guru skill, you can paint the diablos and keep shooting without caring about the health.
To get this skill just insert five Perceive jewels. This is just my favorvite skill and helped me finish my first HR9 quest.
If you disagree with this post what this topic needs and if you have any comments(please no bad comments, this is my first hint)then feel free to post. If you have any suggestions on what else I can do feel free to post.