The company’s Pistol Magnum model is the IMR 4227. If you want the real Magnum speeds and performance, you need to go with IMR 4227, so says Magnum. This powder is especially useful for the Hornet 22 and the Fireball 221 because it increases their speed and accuracy.
The loads shown in the reloader guide should not be exceeded.
Do not mix two powders, irrespective of type, brand or source.
Never replace the black powder or black powder with any smokeless powder.