DF, a 10 or 12 twist works real well with the .358’s. My two Whelens both shoot the 250’s fine even with the 16 twist but I’d prefer more RPMs myself, especially with the all copper bullets. I don’t believe the extra RPMs will go to waste assisting opening the copper bullets.
I have two 35 cal barrels waiting to find a donor like yours. Ones a 9.5 and the other a 10. No harm in getting extra and I’ve not seen any detriment to it.
I’m pretty jealous of the little 358 Featherweight you’re having made up. I’m betting he won’t stamp it unless you ask him to. I’ve sent a couple P64’s to him and he’s left them unstamped since he says a nicer stamp job could be found than his usual method.
I am looking forward to seeing what you do with the old rifle. I love breathing a little life into those old rifles and gettin a somewhat rare chambering is pretty fun as well.
