Congrats Iowahunter!
The .260 is a great round. I have a 15" one by Bullberry. Limited loading experience thus far due to running out of time for Hunting season. So far have used 100 gr. sierral hp for initial break / sight in loads using 32 and 35 gr H4895 (light loads). Did manage to get a couple of groups @ 1".
Also threw together some loads of 120 gr speer hot core with 36.5 gr rl15, pretty accurate. Also 120 BT with 36.5 gr RL15, again groups hovering around 1.0~1.25". Not bad for initial loads and getting used to first time shooting handgun @ 100 yds.
Caution: recoil is not bad. Muzzle blast is horrendous. First time i ever had to wear both plugs and muffs. " Fire in the Hole" shuts down and paralyzes the the range members, definately do not make friends.
This is common to any short bbl. cartdride of this class.
Enjoy.
Mirage.