Several companies make 9mm barrels that will fit the .40 frame. I have one that works fine but I don't remember who made it. I did have to swap recoil springs until I got the action that I wanted. IIRC I have a 20 lb. spring in now.
If you're getting chewed up, it sounds like a different problem entirely. I swapped hammers on my HPs and I don't get bitten any more.
You might try the folks here at the Browning fourm.
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