This is who I used for the test of the German 7.62 NATO "Ubüngs" ammuntion. Our Fulton Armory M21 ( the one I built from their barreled action and a CMP M14 parts kit ), our FN Israeli Mauser, and our Spanish FR-8 Mauser. Short answer - the longer the barrel, the better the performance. It will not cycle the semi-auto(which I knew already) but is good for plinking, close-in practice for accuracy and form, and I don't know about at range. I was shooting at steel targets and couldn't...