As part of my ever-expanding collection of conversion pieces and specialist kit, I purchased a set of boarding shields a year or three back, intent on creating a unit of Boarding Marines as described in Imperial Armour Volume 9. With my Heresy project picking up dangerous levels of speed, I decided to finally use the boarding shields in my collection and combine them with a unit of 10 Marines in Mk4 armour to create a Legion Breacher Shield Squad that looks pretty sweet despite the distinct lack of Mk3 awesomeness.