I tested the 286 grainers swaged down, and velocity was fair at 2,175 at 41.5 grains of reloader 10x with a CCI Bench Rest Primer. The cartridge was far from being compressed and I'd estimate the case consumption to be at 95 percent.
Due to this, I decided to go to a longer spritzer with a much higher BC.
After reading of an Australian gent shooting wild boar with some 275 grain protected points at low impact velocity, I was sold. He purposely loaded them to test for expansion on boar with impacts around 1,800-2000 fps. The boars had severe wounds and expansion was evident in every occasion. He failed to retrieve a bullet, so he purposely shot a downed boar from one end to the other while being careful not to hit bone. The recovered bullet had expanded wonderfully, and weighed 265 grains or so. His field test can be found here:
Using once-fired 358 Win brass, CCI Bench Rest primers and reloader 10x, I started at 42 grains, 43gr, 43.5gr, 44gr, 44.5gr, 45gr.
At 42 grains of reloader 10 x I saw 2,200 fps. This was promising and I was enthused, figuring I might reach my 2,300 fps goal. Case looked good, extraction was easy, primer was slightly flattened. Shucked the second one in, chrony read "duplicate", real promising. This is where I hit the problem, I shucked the cartridge with 43 grains into the chamber: 2,240 fps. Extraction was difficult. I was confused. I looked over the case, and the brass had a nice shiny mark on the head where the extractor groove is cut out of the bolt face. The primer was cratered, and the brass had grown in length by .008". It was at this point, that I realized I made a HUGE mistake. I forgot to wipe out the heavy coat of tetra gun oil out of the chamber. This caused the brass to not expand properly, and put more bearing against the bolt face, then the brass flowing back into the chamber. This oiled chamber in combo with a rifle the locks up at the rear, was is a major no-go.
I'm satisfied that at 42 grains (97 percent case capacity) with a heavily oiled chamber, I got 2,200 fps from an old 20 in. barreled Savage 99 with no excessive pressure signs, but not satisfied enough. At this velocity, this bullet would be almost equal velocity at 300 yds to a 250 grain Swift A-frame at 2,300 fps. Again, the high BC makes this possible. They would both be within an inch of drop at 200 and 300 yds. I will try one more time with a dry chamber, and resized Lapua 308 brass to get beyond 2200 fps.
Anyhow, If yah didn't click on the link, here's picture from that forum of the recovered 275 grainer (on the right side) with excellent expansion at such a low impact velocity (didn't hit any bone):