Trying to put together a light weight hunting rifle in 6.8 Western. Is there enough of weight difference in high end optics to make much of a difference? Is the a “go to” option that I should consider? Thanks in advance.

The answer to this will be determined by what you expect out of the scope, and "light" relative to what other scope?  

How far do you intend to shoot with it?  Dialing or holding for corrections? Budget?

Vortex Razor LHT 3-15x42, 19oz.

I have one NIB if your interested

What top and bottom end power do you want?  How far you trying to shoot?  Are you fine with SFP or do you want FFP?

Leupold VX5/VX6 and Razor 15x LHT are fantastic light SFP scopes. The 8x and 10x Razor LH are too and the SWFA Ultralight, too.  All of those are going to provide great Japanese glass.

FFP tend to be pretty heavy. The 22X Razor LHT is really really light for an FFP.  March and NF make some weight conscious FFP scopes - but they’re $$$.

High end optics can range from under 20oz to over 40oz. It really just depends on what your needs are. If you want something that tracks reliably for longer shots it’s going to weigh more, if you can keep that under 30oz you’re doing pretty good.

The Swarovski scopes with the BRH reticle are awesome if you’re trying to keep things light. It’s a very simple mil based tree reticle and on a 6.8 Western should get you out beyond 700 yards with holds and the Z3 3-10 version weighs a hair over 12oz.

Keep balance in mind though, the only think worse than a heavier rifle for hunting is an unbalanced rifle. If you’re going to have a suppressor off the end you’ll likely need more weight in the optic for good balance.