"The contract is expected to be finalized within a week. The US firm will have to deliver the rifles within one year from the date of finalising the deal," said a senior official involved in the negotiation of the deal said.
Army sources said the US-manufactured rifles will replace the Insas rifles.
The world's second largest standing Army has been pressing for fast-tracking the procurement of various weapons systems considering the evolving security threats including along India's borders with Pakistan and China.
In October, 2017, the Army began the process to acquire around 700,000 rifles, 44,000 light machine guns (LMGs) and nearly 44,600 carbines.
Around 18 months ago, the Army had rejected an assault rifle built by the state-run Rifle Factory, Ishapore, after the guns miserably failed the firing tests.
Following it, the Army started scouting for rifles from the global market.
The procurement of assault rifles has witnessed significant delays due to a variety of reasons including the Army's failure to finalise the specifications for it. The Army needs around 700,000 7.62x51 mm assault guns to replace its INSAS rifles.