Common aircraft acquisition strategy in military helicopter aviation is that when the cargo and utility aircraft have longer legs or are faster than the gun cover; get a better gun cover provider.
The US Army tried to defeat the high long-term cost of this method by getting way out in front of gunship need with the Advanced Attack Aerial Weapons Platform (think that’s pretty close), the Cheyenne.
But they needed an interim aircraft to fill the gap till the AAWP could be built and fielded. Bell built the interim aircraft from current experimental designs and lots of off the shelf parts.
The Cobra.
Pretty good interim aircraft I'd say.