As Jim and Mike pointed out, steel is much easier to engrave than brass. Cast brass can be difficult due to uneven grain structure while sheet brass tends to have a grain that runs in on direction, almost like wood. But don't worry, just keep practicing learn to be self critical and you will be fine. Look closely at original engraving as done by colonial gunsmiths. With few exceptions, most of their engraving was pretty rough and poorly executed. We have much higher standards and expectations. We compare engraving to pictures we see of the finest engravers in the world. The typical frontier rifleman would have been dazzled by any crude scratching on the metal of his gun. Not to say you work can be poor, but don't beat yourself up if it is not perfect, practice constantly and have fun.