First of all replace the mainspring and the recoil spring. A lot of officers have tried to make the original mainspring into a "D" spring by simply shortning and you have no idea how many rounds have been through it and how it was kept.
I use Machinegunner's lube for the rails and the falling block under the barrel. While you're at it make sure that the falling block is lubricated as well as it is the lockup mechanism for your weapon. Make sure the pin moves freely and easily that actuates the falling block. The weapon is a genuinly good handgun. I trust mine with my life every day and have put over 7,400 rounds through it to date without a single malfunction. WWB ammo is generally very good ammo and very consistant, I've shot a ton of it without issue. Make sure the slide moves freely and easily unloaded and the action is quick and crisp once you have replaced the springs. http://www.olhasso.com/PS/ is a great parts source today's notice advises that he now has in stock Elite II hammers, D springs, locking blocks, he has recoil springs as well. Go to http://www.beretta92fs.com/ for great video instruction on the weapon to R&R just about anything. Let us know how you come out. I've used the weapon in the 96 version as well as the 92 for years without any single failure, I hope this helps you with your issues.