My uncle shoots a 30-404 Improved, which is almost exactly the same thing as a Tomahawk.
His rifle weighs 16.25 pounds and has a muzzle brake
. When shooting the highly efficient 240 grain Sierra, the recoil is very stiff, too much for me to really enjoy shooting. Without the muzzle brake, it would be a real picnic. Maybe you are use to magnums and wouldn't mind it at all but you'd definitely need the brake on there.
How far do you need to shoot? The 6.5-284 has minimal recoil, is very accurate, and will kill out to 1,000 yards.
I am about to build a 300 UM for myself but mine will weigh in around 35 pounds.