[1][2] It replaced the putting out system, where contractors worked in their own facilities.
Inside contracting was the system favored by the Springfield and Harper's Ferry Armories.
The manufacturer hired inside contractors and provided materials and machinery.
Each inside contractor was expected to hire his own employees and meet certain production and quality goals, but everything else was left to him.
For example, it was to the inside contractor's benefit to allow machinery to deteriorate toward the end of his contract since maintenance was costly and he might not reap the long-term benefit if he didn't get another contract.