The article shows it as 7.62?
I got that from Wikpedia. I scanned the article and couldn’t fine the caliber. I am guessing the article is correct and Wikipedia is outdated.
Evidently the SDM-R designation was given to a previous iteration of the rifle. The new version is 7.62.
https://www.tactical-life.com/news/army-sdmr-csass-762-ammo/