Hello, DesertDog! I owned a BHP in .40S&W. I had the following done:
Trigger job w/stop
C&S ball hammer
Novak Fixed Sights (plain blk-on-blk)
magazine disconnect removed
spegel blk checkered delrin stocks
Having been used to the feel of the 9mm HP, I could never get used to this gun's extra heft and preferred the 1911 to the .40 HP. (Strike One)
I really don't care for .40 in the first place and my particular gun was not very accurate with more than a handful of loads, the best factory load being WW 155 gr Silvertips and a handload using a 180gr CFP.
My gun was very load-dependent for getting acceptable groups. (Strike Two)
My .40HP was not reliable except with certain of the Browning factory magazines! This includes Mec-Gar 10rnd magazines! I found that out after ordering 10 of them. None worked in MY gun. (I noted that the followers in the Mec-Gar mags were very close in design to those we're all familar with in the 9mm while the Browning/Mec-Gar version's follower had kind of a skirt that came down and held the front of the follower up more.
I should note that these same "unreliable" Mec-Gars worked fine in friends' BHP forties.
The mag release did not seem to be letting the magazines hang down any more than factory and measurements taken with calipers showed no undue differences.
(Strike 3)
You are probably aware of a fellow who took a .40HP and got a BarSto for it in 9mm, three lugs and all. He really likes it as he has a
tough platform from which to fire loads of the hot stuff. I like the idea, but much, much prefer the standard size 9mm HP. I shoot quite a bit of warm/hot handloads through my BHPs and have not sheared/rounded any lugs nor cracked anything....so far, but I routinely replace the standard recoil spring with the 18.5lb conventional from Wolff and do use Buffer Technology's shock buff. This systems worked fine for me.
For me, personally, there's no contest: I will stay with the 9mm HP and prefer the MkIII version for shooting. If the caliber designation starts with a "4," I prefer the grand 1911.
Best.