>>63885547
It was Sweden that purchased 15,000 of them as a stop gap solution.
Their own domestic AR variant is being manufactured by Sako in Finland, but the Finns can't produce them fast enough.
The M4A1s will be used to train conscripts until sufficient numbers of AK24s are available.
It's unclear how the carbines will be employed afterwards, but it's widely speculated they'll be issued to the home guard.

These M4A1 carbines weren't purchased directly from the manufacturer.
They were purchased from the US government and pulled out of the US Army's stockpile of new-old-stock.
As far as I'm aware this batch includes both Colt and FN rifles.

Pic one of the M4A1s Sweden purchased. With the typical issued accessories.