Originally Posted By: Winny FanWhen the 204 Ruger first came out, the big thing that Ruger and Hornady supposedly wanted was to produce the fastest commercial cartridge which meant convincingly besting the 17 Remington velocity.
The 223 based 20 caliber off-springs that they initially tried did not safely give the necessary velocity, so the 204 Ruger was created from the longer .222 Remington Magnum case which allowed a bit more case volume over the 223 Remington. In addition, Hornady had produced a 33 grain 20 caliber bullet for quite a few years to meet the needs of Tactical 20 shooters and others who shot a few other 20 caliber wildcat cartridges long before the 204 Ruger was "invented". In order to get the needed velocity in a safe manner for the 204 Ruger, the bullet weight was reduced from 33 to 32 grains. (I still have a small stache of the 33 grain Hornady bullets that I had stockpiled for my Tactical 20 that I had built in @2000.)
Those two things, coupled with a standard chamber with a bit of extra free bore ala Roy Weatherby, made the 32 grain Hornady 204 Ruger loading the commercial velocity king.
Now that the world had suddenly "discovered" a new bore diameter with the introduction of the 204 Ruger, it wasn't long before some 223 based 20 caliber wildcats were created, one of which the internet told us was the "brand spanking new" 20 Practical - a simple neck down of the 223 Rem case. In fact, 20 caliber shooters had been loading and shooting the cartridge since the early 1980's. The just called it the 5mm-223. In addition 20 caliber wildcatter had shot a cartridge for years based on the 222 Rem Mag, which for other than a couple of very minor dimensional difference, looked amazing like the "new and totally innovative" 204 Ruger cartridge.
And that is how I remember it.
While searching for an ultra light Predator rifle in a 17 Rem. I found the Kimber Montana in 204 which of course met all of my needs. Winny is right in saying it doesn't take to long researching loading manuals and observing chronograph display readings to notice that other 20 cal. or 24 cal. has to be pushed a lot to match the 204 velocities. The same holds true for the 17 Rem. vs the 17-223. Not a thing wrong with the other 20 and 17 calibers, but it's hard to overcome case volume. Similar to the old saying of cubic inch eventually takes over.
So to end my rambling, I am a big fan of the 204 and hope it stays.