I am a semi-auto guy and recently purchased my first revolver. It is a used, stainless 4" model 65-3 in .357 mag. I don't know much about revolvers. Can any of you wheelgunners tell me anything about these guns? Thanks.

It's based on the 'K' frame and is a good gun if you don't feed it a steady everyday diet of 357s. BTY what I mean by a steady diet is over a couple 1000 rounds of 357 a year. The Model 13s and 65s were designed to handle +p/+p+ 38 spec rounds with "duty" use of 357 rds. They have a fixed sight which usually will strike somewhere in the 6'o clock area at 50ft....just wondering does yours have a pinned barrel or not?  
If you want to feed it a daily diet of full power 357 buy a "L" frame or a GP100. If not and you want a good gun for the little lady to use or just to have fun with-- you've made a great purchase...
 Your 65 will probably shoot best with 357 in the 110 gr to 125 gr, incidentally some of the best 357 "manstopper" rounds are in that range. Also these aren't as punishing as the 158 gr 357 rounds
  Get some speed loaders and practice reloading; the safariland models are better that the HKS style.

You have a great gun that will give you years of service and enjoyment. Welcome to the world of wheelguns. Autos are great but everyone who considers themselves a serious shooter should have a least on wheel gun...

Thanks MHPDblue, I am not sure if it has a pinned barrell. I plan to get a speedloader, and I have already bought  some Bianchi speed strips for a compact reload, as it will probably spend most of its life in my girlfriend's glovebox. I got some Winchester PD 110gr. JHPs and she loves shooting it with that load. Is it an effective defensive load? What is the velocity, as it is not listed in the Winchester ballistic chart? Thanks again.

Actually, the 125gr loads are considered the better .357mag loads for self-defense. There's several mfgrs who make these loads & there's a bit of varience in performance between them.

The model 65 is an excellent combat revolver.  The FBI used to issue it in the three inch heavy barreled configuration.  Watch-Six