I have 100 and 125 grain Partitions. My 6.5X55 Encore Barrel is a 14 twist. Any suggestions as to which to try first? I'm hoping for 1" to 1 1/4" at a hundred.
With that twist I would try the 100 grain first. The 125 will shoot fine in a 1-8 twist.
Dunno why any barrel maker would put a 1-14 twist in a 6.5x55 barrel.
The Berger stability program says the 125 absolutely won't stabilize, but the 100 probably will.
It's pretty easy to use computer twist-rate programs, so dunno why these questions keep showing up here.
Like MD noted, that is truly an odd twist rate to have in this chambering. Who made the barrel?
I do know of one person who had an Encore made up with this twist rate about 20 years ago simply because he had about 3000 of the Sierra 85 grain HP Varminter bullets and a bunch of Lapua 6.5x55 brass. He lived out west and pursued rock chucks with a passion and also took the occasion coyote. He is getting up in age and recently was parting out some of his stuff. This is a long shot, but if you got the barrel from a guy with the initials JS, I have the recipe he used with those 85s. Target pictures he shared were impressive, to say the least. If that's the case, PM me for his load data.
I do know that he never tried any bullet other than that 85 grain Sierra. As MD noted, don't bother with the 125s. You'll be wasting valuable components. But the 100 grain Partition will likely do OK.
Odd rate of twist, to say the least...