Spindrift
posted this
25 December 2023
In my 1:10 ROT .30- cal rifles, I get slightly oval holes with 200grs+ bullets at subsonic velocities. They still group well. But the unstable flight will be somewhat detrimental to the flight characteristics, which probably motivated the choice of such a heavy bullet, in the first place.
Still, the 1:10 twist is a versatile and good option that will also facilitate the use of higher velocity loads.
I would avoid the bore- riders if you plan to powder coat, custom throat or not. Particularly a design with such a long nose.
I would go with the 1:10 twist, but choose a lighter bullet without bore-riding like the excellent NOE311-179 suggested above. Coated PB is good not only for subsonics, but also for quite feisty loads in more potent cartridges.