D
Deleted member 67409
Accessories will most likely include a bipod and a 2.5-10 x 44 FFP scope. Eotechs are on sale... A three gun piece this is not, additionally, If memory serves me, .308 3-gun is aptly named ‘heavy’, no?
In local matches around New England, like at Townsend in Mass and here in RI, very few people shoot 7.62 NATO, so there's often a Heavy/Heavy Metal division, but not many guys shoot it unless they're using like an AR + .45 + pump 12-gauge. Don't worry about divisions, just take the gun out to learn and have fun.
Bipod: I suggest Atlas. If you're going to mostly shoot from a shooting bench, you'll want one with shorter legs. If you're going to mostly shoot from practical stances like prone or sitting, you'll want one with longer legs.
Optic: depends on what you're going to do with the PTR. The G3 was intended to be a frontline infantry rifle. I'd say go with a LPVO, like a 1-4, 1-6, 1-8, or 1-10 Second Focal Plane. A red dot is fine if you're going to keep shots within 100 yards, maybe 200. 200 could get tough with a red dot. My one piece of advice is to keep optic and mount weight in mind. A scope and mount is going to make the gun heavy. Especially with something with a big objective lens like 40mm, 44mm, 50mm, or 56mm.