Possibly a pressure/litigation issue with 'hot' handloads in cartridges with a greater capacity than the .22H.
While billed as a 'budget priced' and 'value' rifle,
it has been called by Savage a 'rimfire on steroids', and is a rear locker.
I would have thought that it could also be offered as a .222
Most European manufacturers have offered their 'super' rear lockers as .22H, and some even in .222, but none in .223 that I am aware of.
Sean