OR... If after the lightest of the light, instead of building a $4k+ project rifle, you can just buy a Kimber; 4.8lbs short action, 5.3lbs long action... and it comes in .280AI. I built a ~$12,000US full titanium actioned custom (not just the receiver like most Ti's, but the whole action) and it came in heavier than my Kimbers (6.25lbs pre-optics, but it's a .375 2 1/4" Nitro for Grizzly duty).
Many folks seem to insinuate a few extra pounds don't matter, I can assure you they do, but the style of hunts matters too. All my operation's mountain goat hunting is backpacks and boots from a drop off lake, no horses, it's heavily physical naturally. I had an in shape guide from Alaska in his 30's come last year and he puked from exertion, pounds don't matter... Ounces do! I also in the same breath recognize mountain hunting means different things in different places, many have less footwork to do, horses, or easier terrain.
People will bring up the "greats" from the past and their Featherweights that weighed what we now consider a standard rifle, and I'd like to remind them they'd have taken a 5lb rifle if it was available and losing weight can only help. Not all mountain hunting is created equal, either, I caution clients booking you're far better off with a sub-6lb .270 Win than an 8lb .300 and the lighter rifle will bring you more opportunities and a better experience.
Yes... I agree the easiest place to cut weight is on your body, and that's a continuing challenge for clients. But all else being equal every ounce we can cut, perfect, every
pound... Well no further explanation required! I fly into extremely marginal alpine lakes at high altitude and saving every smidgeon of weight there is a safety consideration too. As soon as one says "It's just a few pounds" the slippery slope has begun. The good aircraft manufacturers understand weight and one of the helicopters I fly at the day job is running a wire reduction program right now to cut grams... Let alone pounds.
I'm admittedly weight crazy, gear is shaved to the bare minimum as for where I operate it brings better experiences. Where lmart is and for what he's doing his new rifle could well be perfect, though if he was booking a mountain goat hunt here I'd suggest he picks up a Kimber to beat up and leave his nice new build at home. He's not, and I wish him luck in the fall on his sheep, it'll no doubt kill them nicely and I'm interested to hear how it shoots. No doubt extremely well like all stuff that rolls out of Rick's shop.
As for the tough crowd, this is the internet, bring a helmet.