my kit was a new ball and spring that goes under the ejector. Very simple but before installation, easy 90% of the time it would not eject the fired case, afterwards, I honestly cant remember a failure to eject it, and I have probably shot 150-200 rounds thru it playing with different loads and setting to get the girl settled down. Appears not to like the 55 or 53 grain vmax but does like the 55gr sierra blitzking and Nosler 55 gr varmegeddon FBT.