Here is the info about the conversion from the website. 460rowland.com
"The Mighty 460 Rowland Cartridge delivers true .44 Magnum power, accuracy and range in your favorite, light-weight, easy shooting, .45 caliber auto-loading pistol with much less deafening noise, night-blinding muzzle flash, target-obscuring muzzle rise, punishing recoil, and far greater volumes of fire than Dirty Harry’s .44 Magnum ever could. All this has made the .460 Rowland the single most successful, independently developed cartridge in history. The Authentic .460 Rowland cartridge uses extreme chamber pressures to achieve it’s .44 magnum muzzle velocities and will propel a 185 grain bullet from a five inch barrel to 1550 fps and, unlike a standard .45 ACP cartridge, it realizes 20% higher velocities when fired from an eighteen inch barrel. This makes our soon to be available .460 Rowland carbine accurate and devistating to 150 yards.
In order to prevent our high-pressure round from being chambering and fired from guns that may not be up to the task, the .460 Rowland’s shell casing is 1/16 of an inch longer than a standard .45 ACP cartridge. Due to their identical overall length, however, an Authentic .460 Rowland Conversion will reliably feed and fire standard .45 ACP cartridges from standard .45 ACP magazines; just like the .357 Magnum feeds and fires the .38 Special… only bigger… much bigger.
Standard .45 ACP reloading equipment may also be used to load .460 Rowland cartridges and owing to ten plus years of market success, lots of loading data are readily available. Factory ammunition and brass are also available from a number of other quality manufactures, although we take great pains to insure ours is more consist than you will find anywhere else. One would expect nothing less form the inventor and developer him self.
*”Johnny’s Personal Carry“: (shown here ), is a 185gr, hard, well balanced, jacketed hollow point and “will do just about anything you could ask a pistol round to do”. Like a good politician,it is the compromise most useful in a wide range of applications.
For those of you not interested in compromise we will soon be offering ”Johnny’s Large and Dangerous Game” round and “Johnny’s Home Defense” round. Hard and heavy for maximum penetration on one side of the spectrum and light, fast and disintegrating for maximum kinetic energy while keeping innocents safe on the other.
For Maximum Fire Power: holster an Authentic .460 Rowland/Glock-21 Conversion, load it with a 26 round magazine, (put one more in the chamber), and you have a very light weight, utterly reliable, “Tack Driving” “Hand Cannon” that is capable of placing over 27,000 foot-pounds of muzzle energy well over 50 yards down-range faster and more accurately than any other pistol on the market today. This .460 Rowland configuration delivers more than four times the fire power of Dirty Harry’s .44 magnum revolver, three times the fire power of the Mighty .454 Casull revolver, and twice the fire power of the 8 round .50 Caliber Desert Eagle. All this from a pistol that is much easier to carry, to shoot and to reload than its monstrous counterparts.
An Authentic .460 Rowland / Glock-30 Conversion is the smallest, lightest, most reliable, and most powerful handgun legal to carry in most states available in the world today! Stick that in your boot and see how it affects your stride.
If you prefer one of the many high quality, time tested, 1911 style pistols or one of the the absolutely marvelous Springfield XD and XDm style pistols, we also have the hardware and ammunition to upgrade these superior handguns to true .44 Magnum performance levels, without asking you to give up the easy shooting, light weight, high capacity, auto-loading pistol you have come to love.
We hope you enjoy the cartridge and pistol conversions Johnny has developed for you, and we look forward to keeping you happily supplied with the most unique and effective pistol cartridges and shooting platforms available today."