Old timers I knew have said if you're going to be shooting cast lead 223 or a conversion kit such as this, you will want to fire 5-10 rounds of actual 223/5.56 for every 100 rounds of 22 or the gas tube does tend to get plugged (it isn't used to cycle the bolt but the gas system doesn't just disappear with a lil kit like this). Keeping in mind of course that when you do that, you'll have a chamber full of lead dust. Your mileage may vary.