Pathfinder Archery Sniper: little to no casting, 1st party only. Doable?

[Efrate]

Trying to help a player of mine make a sniperish character in pf 1e, and running into walls.

1st party only, no traits, norace builder, and little to no spellcasting, this includes UMD abuse.

9th level is the target, will be a member of an unknown composition party.

Is there a way to get a single big attack ideally from hiding? Something like archer fighter with sniper rogue and vital strike seems okayish, but not sure how effective it will be? Will be running rise of the runelords picking up where last group ended, in the stone giants fortress.

Was thinking something like orc hornbow somehow size increased twice or once with a large PC to get damage dice up, but with his wants of little to no spellcasting nor UMD trying to make this work is painful to say the least.

Figure 25 point buy.

Any help is appreciated.

[Kurald Galain]

I suggest using Furious Finish, and possibly Shikigami Style.

But yeah, you basically want size increases with Vital Strike, and it's kind of hard to get those without spellcasting. Maybe do one level of cleric, restrict your spellcasting solely to out-of-combat healing, and use the Plant domain to enlarge yourself as a swift action? That's not a spell.