I installed on one my buddy's Greek-made HK91-clone a Springfield Armory SAR8. Works like a champ. You can remove the rubber buffer without scratching the finish by gently prying it loose; I know, I know, I know, it will scratch finish, but be VERY CAREFUL, it can be done, because I've done it.
You can reload the dinged up cases, it just looks bad, but fires like a champ with the familiar longitudal lines caused by the fluted chamber.