RE: Fire-Forming .280 Improved
Talked to my gunsmith today. I asked him about headspacing. He said he uses the regular .280 Rem "go" gauge as a "no-go" gauge for the improved, and he has a special "go" gauge he made. It should take some effort to close the bolt on factory ammo, in order to hold the brass against the bolt face for fire-forming. Like you were referring to, Roskoe, bullet seating depth shouldn't matter.
The rifle should be done next week. I plan to use lightweight Talley rings, and a 3.5-10x Leupold VX3 with the B&C reticle. The range I usually go to closes for the month of December, so I may have to wait a while to shoot it. There's another range, further out of town, but I rarely go there. I may see if they're open.
BigBob, if you ever find yourself making a return trip to Alaska, please look me up. I'd be happy to take you out halibut fishing.