A U.S. technology company made thousands of digital-gun files publicly available, including blueprints that will enable users to make plastic guns with three-dimensional printers, a scourge of gun-control advocates.

Cody Wilson, a director of the company, Defcad, has waged a multiyear legal battle against the federal government over the right to share 3-D-gun-related materials. This was the third time he has released such files, but the first time he has abided by U.S. foreign export controls online, using what he said are digital verification tools to ensure legal file downloads.

Mr. Wilson said he believed his release of the files would be “impervious” to legal challenge and would help normalize the distribution of such material for easy download in the future.

Mr. Wilson is offering access to the files for an annual fee of $50, characterizing his service as “Netflix for 3-D guns.”

His opponents quickly condemned the action, saying that he is bypassing federal gun laws, including those providing for background checks of gun buyers. Foes are also concerned about the proliferation of 3-D-printed guns, which don’t have serial numbers, making it difficult for law-enforcement officers to track them should they be involved in a crime.