I recently acquired the USAriadna starter box and I'd like to convert one of the grunts to a sniper. Which grunt should I choose and what suggestions do you have for the conversion? Thanks!
Get the spec ops (the hooded one, I'm not sure if the grunt version has a weapon sprue) and use the sniper rifle as a straight swap with either of the two men, the woman is too small to look right, and since there's already a female sniper in the SWC box, it's a waste of time anyway... Or if you aren't dead set on using 100% CB parts, you can get one of the scoped guns from a warlord games modern military sprues and either use it as a swap or chop it up and glue a scope and barrel extension to one of the grunt rifles.
If costs are not an issue: Standing grunt USARF starter + arms of Marauder sniper and some greenstuff (not much)
Easiest way - shorten the mag, drill above the muzzle, stick a paperclip in and put some plastic over it. Headswap is optional. I actually bought this mini converted this way, but I like it - I ll just add a bigger scope before painting.