I've had my 260 for a month or so, and broke it in with some factory ammo, and some 123 Amax, while waiting on my 260 mod case, so I could find the lands. I wanted to shoot the 123 Amax, but Jon said the 139's shot great with an 8.5 twist, and he was right.
The gun is a Trued up, BP Rem 700, 24" Krieger MTU 8.5tw 4 groove barrel, with a PA M41 Brake, enlarged to fit brrl by Jon, Kampfeld bolt knob, bedded in an HSP, and waiting for a Mcree or Rock Solid. I was hoping for a 1/2" gun for Tac. matches, but it's hanging right in there with my BR rigs to 3/600yd.
Gun shot .5-.8" until I got some H4831sc then it turned into a whole different gun.
1st 8 shot group at 100, with 1 called flyer @ 100
Next 5 shot group at 150 yds with 45.1g H4831sc.
It was running around 2700, within the 1st 20-30rds, but the brrl seems to be speeding up a tad, as Saturday it was clocking around 2800, but today was showing 2750-2780, but I don't trust the borrowed chrono, but the drop seems to be in line with 2750. Only been shot at 600yd once, and 300 a cpl more at steel. I hope to stretch it's legs soon at Oak Ridge Tn. Thanks to a member here VarmintH8R for making me a mod case. Thanks again VarmintH8R!
Also thanks to Bob Beck for a new NFNXS 3.5-15 with Vel. 1000 MV.5 ret, Seekins rings, and PA 20moa rail, and to Jon Beanland for building the most accurate rifles in the world. Can't wait to get it on a bench, and get a good rest.