I have built a Cpl dozen ultralight/lightweight rifles and this is how I break it down weight wise when we have a goal in mind for the scoped weight, Talleys and a VX3i 4.5-14x40 30mm CDS scope add 1lb to the bare rifle weight
Ultra Light 5-6lbs scoped
Lightweight 6-7.5lbs scoped
Standard 7.5-9.5lbs scoped
Wheelbarrow rifles over 9.5lbs scoped
One of cheapest routes to build a custom Ultralight/Mountain rifle is pick up and used Kimber Montana in either a 84L or 84M action and order up a #1 or #2 contour ( I use mostly Benchmark Barrels)( contour example )
The Kimber Montana has a kevlar Carbon Fiber stock thats easily altered ie-cheekpiece, high comb or palm swell, all stainless controlled round feed action and an excellent adjustable trigger add in a barrel and your good to go, some pictures of rifles my gunsmith builds for me on Kimber 84M donor rifles
my everyday hunting rifle Kimber Montana 84M action, 5lbs(no scope) 22" #1 contour Benchmark with a brake 24"
Kimber Montana 84M, 6.5 Creedmoor 5lbs 12oz with scope, 22" #1 Benchmark Barrel
Kimber Montana 84M 7mm-08, 21" #1 Benchmark 6lbs scoped
my nephews Rem 700 280AI, Wildcat Stock, Timney Trigger, 26" Benchmark #1 contour, 6lbs on its own or 7lbs scoped
Husqvarna H5000 280 AI, Wildcat Stock, Timney Trigger, 24" #1 contour Benchmark, 7lb 3oz scoped