The mauser 96 actions are probably just as strong as any 98 action of the same era, the Swedes were built with the best steel available at the time. The 98 actions just have a few more built in safety features to protect the shooter in the worst case catastrophic rifle failure scenario. Small ring/ large ring, I don't think it makes too much difference- the Czechs were building small ring 98s known as G33/40's, that were highly coveted by the Nazis, chambered in 8x57 which is a cartridge that uses modern pressures versus the lower pressure 6.5x55.
I've seen one account of a mauser 96 blown up- a novice reloader who wasn't too bright, filled 6.5x55 cases with bullseye and a 140 gr bullet. The bolt was sprung, the action was bent, the left side of the stock was splintered, but the shooter was uninjured.
That being said, there is no reason to hotrod these 100 year old rifles, they tend to perform really really well at velocities around 2500 fps.