I was thinking about what would be good for 600 and 1000 yard prone matches, and those big 338 bullets going slow still have very low wind drift. Sights have plenty of elevation, and you can always get an angled base, so scope elevation isn't a problem either.
I was thinking a 338-08 Ackley might spit out the 300 grain SMK @ 2100 fps.
What about the 338-06 Ackley? 2300 fps? Recoil would be pretty low in a heavy match rifle.
Even at 2000 fps, the 300 grain SMK beats all 22 calibers at 223 velocities, and some slower 6mm's. At 2300 fps it beats all 6mm's and 22's, and would have pretty much endless barrel life.
In a 15 lb gun your recoil is about 15 and 17 ft lbs, respectively. Is this idea feasible, or should I just get the standard 223 and be done with it? A little case with a big 300 grain bullet seated way out there might draw some attention!
Speaking of unconventional 338's, necking the 300WSM up to 338 seems to have been successful. I don't think it would be too hard to get 2400fps with a 26" barrel (assuming proper throating for the 300 SMK). It would use a short action which is nice.
The 338-08 Ackley would be pretty hot to run 2000fps with the 300SMK.
I'd be surprised if a 338-06 Ackley would have enough case capacity to get it much over 2300, and you are talking a long action.
If some is good and more is better, then too much is just right.
My mind is a raging torrent, flooded with rivulets of thought, cascading into a waterfall of creative alternatives
My understanding is muzzle brakes aren't allowed in any of the matches I've seen or heard about. Even the great shooters are bothered by recoil after 40-60 rounds. Even with a 6.5-284 recoil can be a factor in a long match. At the low velocities you are looking at, don't think you can beat the high BC 243 bullets near 3000 fps. With a muzzle brake, I think bigger, higher BC bullets would rise to the top of many long range venues.
I do think a 338 hunting bullet with a BC near 0.9 would make an interesting carry weight rifle at 338 WM speeds, say 2500 to 2600 fps for a 265 to 280 gn bullet. With a muzzle brake that won't be bad in a 8.5 lb rig. With that BC, would be a 1000 yd rig.
This would be a switch barrel rig, with another barrel in 338 Edge for long range hunting. (and different bolt head)
2400 fps would raise recoil above 20 ft lbs. I could always do stuff to lower recoil, such as mercury recoil reducers, a gra-coil buttpad, but I'm not sure how fun it would be too shoot 88 rounds through in prone.
To varminator, I was at a 600 yard match on Saturday and a guy was complaining about his 7mm-08 hurting him, but then others were shooting M1 Garands which aren't near as heavy as a match rifle and they shot very well. I heard people saying muzzle blast bothered them more than the recoil. But then again, it is about 15 lbs recoil, 50% than a 308 in the same weight gun.