bonefish,
Yeah, the .284 will really shoot. It's problems have been due to several factors. When introduced, many older gun writers didn't "get it," complaining that bullets had to be seated too deeply into the powder space, which is one of the most misunderstood factors in cartridge design. Some even said the same thing about heavier bullets in the .300 WSM when it appeared--and I even heard it from one of the guys at Winchester. But many longer cartridges have their bullets seated well below the neck as well, and nobody complains about them.
Consequently, many writers insisted the .284 should have been chambered in the Model 70, where "bullets could have been seated out where they should be." But the .284 was specifically designed to approximate .270 ballistics in semiauto and lever-actions rifles, NOT for bolt actions. A couple of these writers even went to the trouble and expensive of building .284's on long bolt actions, just to show how it should be done!
Partly because of those sorts of reviews, and partly because hunters back then were buying more bolt-actions that levers and semiautos anyway, the .284 didn't sell all that well. After a while Winchester quit replacing their forming dies for brass very often, and the cases got real sloppy--which didn't do accuracy any good.
Then, when some people occasionally chambered the .284 in short bolt actions, its slightly fatter case and sharper should cause feeding problems.
When Melvin Forbes started making .284's (and his very first Ultra Light was a .284) he made sure it would feed from the Model 20 action. But eventually Winchester brass got so bad he would discourage customers from ordering .284's unless they were advanced handloaders who'd have the time and skill to work over brass, so the rifle would shoot well.
Eventually, however, Norma bringing out the 6.5/.284, so good brass could be simply necked up. Was talking with Melvin about this whole deal again maybe a month ago, and he says Norma's going to make some straight .284 brass as well, with the correct headstamp. So he's back to making a lot of .284's.
I keep trying to explain that the problem with the 7mm Remington Magnum isn't so much "weird pressure spikes" but simply a wider range of pressures, both high and low, with many load combinations, than many similar cartridges in the same power ranges. This was reported to me by more than one pressure lab, one at a major ammo company. With certain powders it's not nearly as much of a problem as others, but there it is--and is probably one reason the 7mm RM never became popular for long-range target shooting.
