To be honest, and thinking the maths and physics on my feet - you would only need a new barrel because the recoil load on firing would be transferred to the bolt, through the bolt, bypassing the bodyside and thence to the locking shoulder (which is well to the rear of the weakened body part). From there it'd travel through the body onto the buffer plate in the butt slide, be buffered slightly and the remainder of the loading would be transmitted onto your shoulder.
There....., find yourself a reasonably good barrel, clean out the buffer mech which is bound to be totally gummed/jammed up and you've got yourself a Bren!