With neck sizing only the cases grow, eventually getting to be tight to chamber, especially with higher pressure loads. My highpower loads were probably middle of the road with the 168 gr and towards the higher end with the 190 gr. Per the manuals I was getting an estimated 2600 fps which seems to work well with the 30.06. Powder selection wasn't as critical with the 168 gr but ball powder like 760 produced erratic high pressures with the 190 gr. I had access to H4831 for $5 a lb for a long time, no longer, so that's what I used for the 190 gr as it seemed to work better than anything else. {Actually 2600 fps also seems like a good velocity for hunting, where you can choose a caliber and bullet for more energy while keeping the same velocity, all the way up to a .375 H&H). I see problems with 'neck sizing' and tight cases even with my pistol loads.
http://www.6mmbr.com/6PPC.html
6MM PPC -- The Benchmark of Accuracy
Developed by Louis Palmisano and Ferris Pindell (left and right in photo), the 6PPC is the "King of the Hill" in short-range benchrest competition, the most accurate cartridge ever invented. It completely dominates 100- and 200-yard Group BR Shooting. If you want to win in that game, you pretty much have to shoot a 6PPC, or some derivative of the 6PPC design.
....Custom Dies Work Best....Most top 6PPC competitors run their ammo at pretty high pressures. Such pressures demand that cases be full-length sized each time they are loaded. But the trick is sizing the case just enough to allow proper feeding/extraction and no more. To achieve this perfect fit, nearly all the "top guns" use custom dies, precisely fitted to the dimensions of fired brass. Typically, a custom sizing die will reduce the case diameter at the shoulder .00075" to .001". The die will also allow for a little bit of shoulder bump. Nearly all the top shooters use bushings for neck-sizing. Having a variety of bushing allows you to compensate for brass that becomes work-hardened. You can also use bushings to tune loads for different bullets or conditions (tighter "grip" tends to increase pressure). For his .263"-necked brass, Speedy Gonzalez has a full set of carbide neck bushings, in .0005" increments from .256" to .261". He also has four different body-sizing dies, which allow him to choose the exact amount of sizing he wants, both at the shoulder and at the web. Most of us can't afford such a collection of dies, so you want to start with a good basic full-length die that brings in the shoulder a little less than one-thousandth. To check if your die is sizing properly, measure the diameter of a fired case right at the base of the shoulder and lock the calipers. Then run the case through the full-length sizing die. Put the calipers back on the sized case and then slide them down. The calipers should slide one-quarter to one-third of the way down the case. If the calipers can slide to the middle of the case, your die is sizing too much.
http://www.findarticles.com/p/articles/mi_qa3623/is_199602/ai_n8741947
Loading for high power rifle
American Rifleman, Feb 1996 by Tubb, G David
The next step is purchasing good tools. It is rare to regret buying the best. Good quality cases combined with precision lies [dies] go the farthest to ensure good ammunition. I full-length size all my brass, including my 600-yd. cases, setting the shoulders back 0.002-0.003". This is an example of where high power loading techniques differ from benchrest-the neck-only sizing that works well in one environment does not necessarily work as well in the other. Full-length sizing assures reliable feeding for rapid-fire and also, I believe, provides better performance in the relatively more generous (compared to benchrest) chamber in the across-the-course rifle.
