They did the same with my AK receiver years ago. It was clear I was talking to a data entry bureaucrat that had no hint of firearm knowledge so I just told him 7.62x39, 30 rounds and 16". That made him happy. I think they had a similar problem with my XCR because they wrote "multi" for caliber. It's a pointless system that no one is going to check up on. So tell them something that will complete their little box with an answer that doesn't cause an error in their system. Don't lie, because lying isn't nice, but don't sweat the small stuff. Years ago I renewed my DL and the lady asked me height, weight, eye color. I said blue for eye color. She looked at me and said "they look gray to me." So my license now says gray. Because my license says gray, I had to put gray on my CPL because they had to match according to some bureaucrat. So now by at least 2 official documents, I have gray eyes. Has anyone come by to make sure my eyes are gray? Nope. Good thing too, 'cuz I think 99% of people would say they're blue.