Ive never, ever had an issue with the short chamber on my model 12 first year 20 gauge. No ripped ends, no excess recoil, no ejection problems, nothing. It has never had a short round in it, in the time Ive owned it.

That said, Im really glad it isnt a 16 gauge. Ive seen LOTS of hung up model 12 16 gauges, from every era.

Best,
Ted