You're much more meticulous in your case prep than I am. I'm just FL sizing, and trimming anything that's over .005" long. All of my brass is range pick-up, though I know enough to keep only once fired. After I've prepped it once, if it goes over length again, I toss it. This is in an AR. I don't even know where my headspace lands, having never measured it. Sizing my own fired brass, it goes through the press pretty easy, so I assume that the chamber is "pretty tight" and leave it at that. I assume that you're using 204 in a bolt gun (?) where you can neck size only. I'm sure you know, but others reading may not: When a case is neck sized only, the case head doesn't get "worked" by expansion and resizing, so it doesn't harden, and the case body doesn't "stretch" as much as with a cartridge case that gets full length sized after every firing. The reason why cases need occasional trimming is because the brass actually "flows" forward. This causes thinning at the web, just forward of the case head, and that's why mine broke. The 204 is an interesting little cartridge. I need to stay away from it, and so many others, because I want my funding and interests to go to "other things". Have you read Vol. 1 of P.O. Ackleys' books? His work with .12 cal. was part of what compelled our gov. to consider small cal./high velocity ammo. He was shooting Antelope, on Catalina Island. He found that even when the animals were hit in the hind quarters with a .12 cal. 12 gr. bullet with an impact velocity of "around 4,000 fps", the lower areas of each lung lobe were purple (bloodshot). He determined that the cause was hydrostatic shock, delivered through the circulatory and nervous systems. DOD did some testing with .12 cal., but abandoned it, because they found that the tiny bore could be obstructed by condensed water droplets that formed from ambient humidity. Who woulda' thought? PS- On re-reading, I see you said that you're FL sizing the 204 brass. Is this in a semi-auto then?
No joe, bolt action varmint guns converted for egg killing competitions. These are my factory class guns with big sloppy chambers. I full length size everything but I do it correctly look into the top BenchRest Shooters and you'll find they all do also. Done correctly fl brass can last just as long as neck sizing or shoulder bumped only brass. Some claim even longer. My BR guns generally cannot be neck sized. They run at pressures that demand FL sizing. I would get maybe one neck sizing out of them before they wouldn't fit anymore. The key of course is to toss those die instructions in the garbage. Your looking to set the fl die to bump the shoulders back around .001"-.002" on fired brass. I used to neck size because that was the general consensus of what was best. When I got really serious about winning stuff I ran some of my own tests and started searching on the web. My tests confirmed what others have found. Fl done correctly creates consistency and accuracy is all about consistency. No I've never read any of Ackleys books. Pretty much self taught except for accuracy related forums. I have heard of his hydrostatic shock theories. In one of my 204's I was able to hit 4750fps using the new at the time 26 gn Varmint Grenades. Way too much pressure and no accuracy up there. Just testing to see if the bullet would explode in flight. They held together nicely.
Thanks for being "loading literate". I think that anyone who harbors a fear of guns in general should understand that this stuff is fascinating, and entirely safe, when a person applies intelligence to the process. It becomes an exercise in what you can do with your intelligence when it is applied to extremes in the physical world. I've seen only one example of a rifle and load that would cause the bullets to disintegrate in flight. I was an RSO at the Lee Kay Center in Utah, and it was winter, with snow on the ground in front of the benches. This guy couldn't get his .257 Weatherby to hit a target @ 100 yards. After considerable fooling around, I noticed that there were little black trails in the snow for about 30 feet in front of his bench. Not a good deer load! The fastest I've ever got a bullet to go was just under 4,200, using the Sierra 40 gr. HP in .223. No accuracy, as you note, but that bullet would audibly explode on contact with anything at all. Isn't it odd that there is an "absolute velocity" with rifled barrels? The Germans went to the utter extreme with their 88mm cannon to reach just about 6,000 fps with an inside tapered barrel, but others have pretty much determined that the absolute with a "straight" rifled barrel is just over 5,000. Caliber and charge isn't the determining factor. There's a load listed here: www.6mmbr.com/index.html that comes very close with a pretty standard set up. It's always been interesting to me that ballistics demonstrates that "bigger is NOT better", but close adherence to strict discipline is the only way to an advantage. This has affected my thinking in EVERYTHING.
