I unfortunately am very short fused but although I do feel the anger inside it’s been many years that have not exploded at anyone. I’ve been able to control it to the point of stewing for a while until I can push it out of mind without reacting...or overrecating. I guess my question would be; is not being able to erradicate the feeling of anger itself considered a sin?
Rav Kook explains that there are two types of righteousness. The "Tzadik" is a person who battles his baser inclinations and overcomes them, that is, does not act on them. The Tzaddik still feels anger, or lust, or conceit, but realizes that these feelings will lead him to improper behavior, and he will not be swayed. A higher level is the "Yashar", the straight one i.e. the one who has straightened out all thoughts and inclinations. So, the answer to your question is no, failing to eradicate all feelings of anger is not a sin. Neither is it the highest level of serving G-d. There are, though, certain issues which can give raise to genuine legitimate anger. If I am angry at a wrong done to me then I am selfish, but anger over injustice in cruelty is in place, especially if it leads to positive action to correct those wrongs. I think your accomplishment thus far is praiseworthy and very special. I pray for your (and my, and all of our) success in improving not only our actions, but our personality and emotional reactions as well.