An A5 with less than a box through it should function properly. I'd concur with the floatinghat and do some homework to start. Take a peek at barrel stamp (pushing 3" rounds through a 2.75" rig is a no-no and the proud hulls will likely not eject), then extractor, ejector, gas ring orientation to start. Although unlikely, she could be short-stroking if you're using light trap loads in a 3" gun too.