I don't see anything wrong with trying to enhance performance of a certain cartridge for certain specifications, i.e. loading up a .30-06 or a .270 a little 'hotter' for a moose or elk hunt, but he key word here is "little"......and there are other factors that come into play when tweaking a cartridge for better perfomance (premium or match grade bullets, consistant cases from the same lot #, ect), not just upping the powder charge and increasing velocity (and pressure!).
Like most of you, I've found that a decrease in a couple of hundred fps in a cartridge will still kill cleanly and at the same time give better accuracy (usually).....
Still, this thread is about NOT reading the manual, or going by memory, ect.....check and double check your loading data.

skeet, There are really sub-MOA rifles out there. It is just that many people don't want to go to the trouble of finding out what it takes to make them shoot that way. In my book, No. 1 is a clean barrel devoid of any copper foulng. Second is usually less than "full house loads". And third, varying the distance the bullet is from the lands. I have always heard stories of how a .22 Hornet is inherently inaccurate. I have two of the accurate ones that can put 5 bullets into less than the MOA if I do my job. My accuracy load in the 30-06 is 1.5 grains less than the recommended military loading for that cartridge. I always tell my son that a prairie dog never knows how fast the bullet was going that gets him.