nice, wouldn't want to be much lighter really, that 280 must get noticed during range time!
5.3 oz would be 1/3 rd of a pound, 4.0 oz is 1/4 lb.
Maybe the nula short in 6.5 grendel will be the full 1/2 lb lighter than the 280? Let me know when you add that one.
Or if i get my ducks in a row maybe i can let you know lol.