It is there but i wont say it is "wide spread". Plus the MAJOR cases of corruption in military procurement have involved civilian Government. The notorious case of Agosta 90B submarines or the Mirage planes have involved Asif Zardari and Nicolas Sarkozi, both politicians.
I do not think this will be the case in the service rifle procurement. It is mainly based on performance and after sales services and side benefits like in house production, getting involved in parts supply, becoming a registered supplier, stuff like that.