Building designs in-house isn't a panacea against corruption, note the entire debacle of the shitty M-14 being selected over the vastly superior FN FAL and the outright revolutionary AR-10.
(According to the Army, the fact that the M-14 was a little bit lighter than the FAL was a hugely important advantage, but the fact that the AR-10 was much lighter was not important at all. Similarly, the fact that the M-14 was a less developed design than the FAL was dismissed as unimportant, yet the fact that the AR-10 was less developed than the M-14 was supposedly a crucial shortcoming.)
(According to the Army, the fact that the M-14 was a little bit lighter than the FAL was a hugely important advantage, but the fact that the AR-10 was much lighter was not important at all. Similarly, the fact that the M-14 was a less developed design than the FAL was dismissed as unimportant, yet the fact that the AR-10 was less developed than the M-14 was supposedly a crucial shortcoming.)