From Ammoland:

Rep. Masse was referencing an interview that Mr. Dettelbach did with CBS’s “60 Minutes.” It was the same interview where the ATF’s firearms “expert” could not disassemble or assemble a Glock pistol. In the interview, Dettelbach pointed out that someone could buy a Barrett .50 cal in cash. He said that FFLs should report cash purchases to the ATF. Many in the gun community took issue with this statement because it is not illegal to buy firearms with cash, and in many cases, gun owners prefer to use cash, especially since programs such as “Operation Choke Point” exist.