I have both chambers and unless I'm mistaken, the cartridge headspaces off of the casing...so you may wind up with some serious blow back if it ignites...
I've heard/read the question being posed before, but never remember any follow up posts with the results....Hopefully it wasn't due to the person experimenting and losing their eyesight and unable to see the keyboard...
A few years ago, I was directed to a gun smith by a customer service rep from Para Ordnance for getting my P-16/40 barrel reamed out to shoot full 10mm rounds, since the magazines will hold the cartridge...
When the NRA meeting was in St Louis, I was talking to the head of Para Ordnance and congratulated him on the excellent customer service for the referral...His comment,:
"If you give me the name, I'll fire him as soon as we get through here."
He was afraid of the consequences if the reamer went too deep and left that kind of potential...his liability was shining then..
It's certainly your decision, if you decide to try it, but an after market barrel is much cheaper and safer..