I built the first on with a 1 in 10 twist and the second with a 1 in 9. You can push a 70 grainer to 4400 fps and a 90 grainer to 3900. I'm shooting a 90 grain Accubond around 3500 to 3600 fps now. I slowed it down a little, because the heat has quite a influence. I tried the new 107 Lapua Sensars L's and they shoot real good, but they are not a hunting bullet, so I'm using the Accubonds. I tried the Bergers with no luck. They willnot handle the speed.
Hi,I saw in an old post of yours that you shoot the 6mm mach IV.I am currently building my wife a 22/06.As soon as its done I am starting on a mach iv for myself.I want to shoot mainly 69-70gr. with maybe the 85-100.Just wondering what twist to go with the barrel will be a pac-nor 28-29"........thanks for any help you can give........Ken