You'll be looking at maybe 2oz per inch of barrel, give or take. Its most likely 24" now. So going to 20 would save you 8oz, maybe.
You can't get a much lighter stock.
Fixed objective scope would save a few ounces.
Getting the barrel fluted might get pricey. I'm not sure, but I think you'd want it stress relieved after fluting.
You can get a brand new barrel in any length, material and fluting you want for under $400.