I can see a M-1 type action with a detachable 8-round magazine as a dangerous game rifle.
The Italian BM-59 is in 7.62 and features a 20 round detachable mag.
There are various conversions around that fed the Garand with a BAR mag(Military rifle).
One of these used as a basis and with sound engineering would be just that, though I can't think of too many bear that would shrug off 8 well-placed 220 grainers. .35 Whelen would be even more formidable.
