“3. Browning Highpower 40SW converted back to 9mm”
And the purpose behind this is what?
Hotter 9mm +P+ was the recipe back when the 40SW variant came out. I was still active duty, had the cash to do it and had one built, by Cylinder & Slide .... Great concept / idea but not really necessary as NDE inspection of both my BHP’s after thousands of rounds of +P+ loads and years of showed no damage .... many pro-con debates to be googled .....
Who can say....:o)