Expert Sniping advice needed, please

Aug 25, 2020
Been sniping in shooters forever, but am now playing a sniper-focused game for the first time—Sniper Ghost Warrior 3, attracted by the open world. Going fine, longest headshot over 300m—but now the going gets tough in Act 4, specifically the early 'Bridge' side mission and the 'Get the Red' main mission.

Those require a number of one-shot kills at 400-500m—one-shot because mission fails if the alarm is raised. I've bee using a x12 scope until now, but need longer for this—best I have is a x4-14-24-34 scope.

Problem is when at x24 or x34, with breath control, lying prone and bipod deployed, the scope is still wandering around way more than I'd like—ie getting a decent bead on the target is more luck than precision. Is there a magic bullet—ha ha ;)—or is that meant to be the challenge as the game gets more difficult? I'm playing on Normal difficulty.