Hi!
As far as I know, and I maybe wrong. No mainstream manfacturer, there may be some, but no “name” manufacturer, produces a 15 round clip. Besides that, no ar-15, That I know of, is clip fed. I’m sure someone can google something and tell me I am wrong.
WHEW!!!
Oh, no one produces 15 round magazines either. AFAIK
You can pick up 15 rounders. Midway sells them. I suspect they are out there for some state hunting guidelines. Dunno, but it is not a standard carry.
Call the police and ask them. Could he have taped 3 10 round clips together and that be what they are referring to as a 30 round clip??? I remember them saying that he had taped clips? or magazines? together.