I picked up two AP5-m MKE's (for excellent reasons) plus I have a PTR-9c. That HK MP5 Chamber Brush Combo (for all calibers) kit is nice, but the MP5 Chamber Face Brush REALLY makes it easy to get the hardest part done well, that entire chamber. I didn't see you use one, but it wouldn't hurt to look em' up. Semper Fi.