I have a .40 Open also. I've been away from competition for a while now, and I was shaking the bugs out of mine right around the time I got away from the sport.
my .40Open:
Para gunsmith frame I got in a trade of prize-table stuff
STI slide, originally decked for a slide-ride Optima.
Clark .40 threaded barrel.
Dawson "Awesome #2"comp, 4 upward ports, 2 sidewards
C-More Serendipity sight with 8-minute dot.
Para factory mag tubes ...I went with .40 because I was in CA and had the high-cap mags. With the Dawson pad,I could get 21 in the mag. Grams pads got me 20.I used the same mags with my Limited gun.
ammo was 140 gr Bear Creek RNFP over WSF powder and Win primers, loaded 1.135 OAL and 172 PF.
now that I'm thinking of getting back into the game, I'll probably try AutoComp.
I tried 155 Berrys plated, but not as good if results, but I could also shoot them in my LTD. Gun.