I'm not sure if you can get anything other than 1 in 9 twist from J & T. I bought a J & T 16" inch upper chrome moley and I feel it is comparable to any off the rack 5.56 from the common manufactures ie, Spikes, CMMG, Stag, Bushmaster or DPMS. Bill stated here that the Shorter barrels 10.5 to 16" did a little better with all bullet weights with twist faster than 1 in 9. Most AA 16" barrels are 1 in 8 twist IIRC.
I've shot a few hundred rounds through 6.5 Grendel and most loads shoot beyond my skill level (1.75" or less @ 100). The heaviest bullet I've shot is 123 grains. I shot one 3 shot group off a lead sled with factory AMAX 123 grain that were touching.
My barrel has the CAR handguard and fixed A-2 front sight. I'm satisfied with my J & T.
I've shot a few hundred rounds through 6.5 Grendel and most loads shoot beyond my skill level (1.75" or less @ 100). The heaviest bullet I've shot is 123 grains. I shot one 3 shot group off a lead sled with factory AMAX 123 grain that were touching.
My barrel has the CAR handguard and fixed A-2 front sight. I'm satisfied with my J & T.