You might want to consider two models for the same thing, so one holding a longer variant Lasgun, and the second one with a cloth covering and sniper rifle poking out.
Just swap out models when not moving them.
Weapon wise Marine scout Sniper rifles are a good choice.
If your ok converting can always go with
https://www.forgeworld.co.uk/en-JP/Elysian-Sniper-Squad and swap heads, add razor wire and cloth (green stuff) to cover part of model, and make the base sandbagged and muddy.