On a Handi you are limited to the chamber end of 1.112"
An octagon section of 28" for a total of abot 31.5 OAL would weigh 5.591 LBS plus the 3.5" chamber end about 0.70lbs for a toatal of 6.29lbs. Cal .458"
Distance across flats are 1.025", Dist. across corners 1.109, width of flats 0.425"
Some body is doing stubbing. Dont know who makes octagon barrels in the US. Ron Smith in Canada will make you one for about $450Can cut rifled.
I made my two Octagon Handi Barrels from 24" 223 Handi bull barrels.