I was in Nichols guns in Rock hill a few months ago and bought a Ruger AR-15 receiver for a pistol project and just because I like to make Bill Ruger roll over in his grave. When I was filling out the 4473 the clerk made a point of telling me that even though it said multi on the lower whatever he put on the form as far as caliber it had to remain because that is what the ATF field agent told him and that I would have to engrave the caliber I make it on the receiver. I made a point of telling him that ATF field agents are usually sociology majors who couldnt get a job after college besides working for the government and don't know gun laws worth a squat until you get into the upper levels and that the agent had probably confused or mixed together some NFA rags with title one regs and just spit some fake knowledge out. He got mad and went away.