conscription does not exist
Conscription has never existed since gaining independence in 1970.  
Oman does have the fourth highest per capita military expenditure of any country in the world. 
The armed forces have difficultiy attracting the requisite number of recruits. About 10 percent of the army rank-and-file are foreigners.
After the achievement of independence in 1970, initially nearly all officers were Baluchis from Pakistan, except for senior commanders who were British.