Sorry to hear your "new" 15-2 is going to need a few adjustments but it's easy to work on them and get the bugs out. I had a few issues to work out on my 15-2 a few months ago when I bought it. When I tried to measure the B/C gap during pre- purchase inspection, I was unable to get any gauge in and there was no gap plus the seller had no wrench and had never had the barrel off. The DA trigger had a problem and the trigger wouldn't return every now and then but cosmetically it in was beautiful shape. He knocked a few bucks off, promised to order me a wrench and I figured I could fix the other issues. The first thing I did was come here for help which was a very good idea. The DA problem was the trigger return spring the seller(his first revolver) had installed himself. The failure of the trigger to return was corrected by backing the over travel screw out a bit. No more sticking. The first trip to the range the ejector rod kept unscrewing and was corrected with blue locktite. This could be part of your cylinder problem. The cylinder stop(little nub on the side plate) popped off while shooting but I found it and red locktite fixed that. I guess sometimes there's a reason someone's selling a gun. I really like my 15-2 and been problem free for quite a while now. It was frustrating sometimes but I learned a lot about the gun during all the tinkering and that's good. BTW, if you're having extracting problems, be careful not to hit the extractor rod to hard because the cylinder stop is pressed in, not part of the side plate. You can knock it out of the side plate if you're too rough on it. Good luck.

I'm sure you set the B/C gap. If you don't have an allen wrench for the side plate screws, you need one. Take the grip off and check for loose side plate screws. Even a little loose the side plate won't hold the hand in place properly and not advance the cylinder. Another thing you can try is check that the trigger return spring hasn't slipped off the "ledge" on the trigger where it rides. Photo shows trigger return spring. Behind the hand you'll see a ledge on the trigger the spring should be riding on. I've had this happen at the range and it will bind the trigger. If you haven't already go to the Gunsmith section of the forum and check out the "Average Joe" tune up. It's a very helpful "how to" tutorial on breaking down your 15-2. It's very simple. Good luck.

Interesting,

I have been shooting all models of DWs for years and never had one " close up" on me. Is it possible that you had some compression on the spring detent ball when you set the gap ? How much torque did you use on the barrel nut ?

I like K frames too as well as J and N

Every time I read where someone has a problem(s) like the OP had, I have to wonder if this is where all the negatives come from regarding DW revolvers? I've owned at least one for over 42 years, about 12 or so total, and I've had a few problems like a too tight grip screw, a couple of barrel nuts put on with red Loctite, a broken trigger return spring, and light primer strikes. All the problems were caused by clueless owners "fixing" things that in most cases, weren't broken in the first place. Putting red loctite on the barrel nut is to me a sign the owner isn't too swift.

One thing I never can understand is how people have problems setting the barrel gap and having the barrel nut loosen up. It's NEVER HAPPENED to a single one of my guns. One time, I switched barrels and forgot to snug up the barrel nut, and fired a couple of shots. No damage, just embarrassment. If the nut is just snug, it doesn't loosen up, period. And if it's really cranked down, at worst it's a pain to get loose. 

I went to the range a year or so ago, and took all three of my DW small framed guns with me. The first one I took out was my worn looking 4"VH 15-2. Not a pretty gun, but it shoots fine. I think I might get it hard chromed, as it looks pretty bad, with maybe 70% of the finish left. The old guy next to me said, "Is that a Dan Wesson?". "Yeah". He snorted and said, "I had one and it wouldn't go a full cylinder without locking up or not firing DA". I said, "You probably didn't adjust the barrel correctly, and had the grip screw too tight!". He looked at me like I was crazy, and I went and shot 4 cylinders worth of full power .357 through it. "Well, You've got that one working, how long did it take you to get it going?". "It came out of the box it was shipped to me in dirty as hell, but it shot fine without anything being done to it". I then took out my really pretty 15-2, this one:

"You've got another one?" "I've got three .357's and one 44 that stayed home!". I shot a couple cylinders of .357 and asked him if he wanted to shoot it. "Sure!". He shot it pretty well, and said it felt like his S&W 686 with a weird trigger. I got out my third one, my $269 deal of a lifetime gun on Gunbroker 715:

After I shot it without any problems, the old guy said, "Well you seem to really have the bugs worked out of them!". I said back, "The only bugs come from people doing weird crap to them like clipping springs and loctiting barrels, and then blaming the gun when it's their fault! These guns are pretty much bulletproof, if you don't goof around with them!". I don't know if he was convinced, but my next gun really shocked him, an Astra A-75, kind of a mini Sig clone. "What the hell is that?". After I told him, he stood there watching me while I loaded up some magazines and cranked off about 27 rounds without any drama. "I've heard a lot of people had problems with Astra guns!". I told him I never had a bad Astra gun, and the A-75 was one of my favorites. He just laughed and said, "You've got some weird guns!". I guess I sort of do, but I have a lot of "usual" guns, and the oddballs, in most cases, are just as good. 

People in general do so many bizarre things to guns, cars, and even radios, it's really no surprise when a DW doesn't work quite right. But since I have a LOT of parts bought over the years, I can fix most anything in minutes. Only part I can't replace is the sideplate. I have at least one of everything else.