[quote=Filaman]
You Nailed it SuperCub. That's about the best explanation I've heard. I have one AI and that's a .257 Roberts. I went with the .257 because for years I always heard the .257 showed good gains. However, one thing puzzles me. The .30-06 case is old fashion also, but the AIs I've read about it were minimul of any gain which leads me to believe there are other factors involved. Maybe amount of overbore has something to do with it.
Re: 30-06 Imp.: 'Tis a confused mess of opinion, preconceived bias, or hearsay, mixed with maybe overly judicious handloading & a low SAAMI pressure for the old 06. Most of my data is from the early '90s with IMR4350, WW brass, & WLRs, but have safely reached 3300fps with 150s, 3200fps with 165s, & a tad over 3000fps with 180s with reasonably good accuracy (all either Nosler Solid Base or Ballistic Tip) in my 30-06 Ackley. It has a 26" barrel. Fully formed cases hold c.10% more water than standard 06. Temps were mostly around 75*, but there were some 30* days in there as well. That's knockin' on, but not quite, 300 H&H velocities. I also started development with RL19 & 150s with slightly better accuracy stopping about 100fps less (max pressure) than the 4350 loads. RL19 peaked out before 4350 with 165s & 180s even sooner. Never did get around to trying RL22 back then. The brass all lasted for 5 or more reloads & some is still loaded in MTM boxes ready to go if the necks dont split after 30 years. Will probably seat the bullets a few thou deeper to break the weld if there is one.
Using Sierra VI data, I recently tried some RL17 matching their speeds rather closely in some of these same old cases. I am curious what pressure Sierra held their loads to as they stop at 2900fps for the 180s in the Ackley, but also show 2900 as max velocity for the standard 06 while showing only a small gain for 150s & 165s with the Ackley. I may continue ever so slowly upward with these but will likely just stick with what is already known to work.
That's the best by far I've ever heard about the 06 AI. With performance like that, who needs a magnum?
