Jake, I'm going to agree with Steamloco here. If it's a new 686 under warranty the easiest answer is to send it in for warranty service.

However, there are a couple of things that you may want to take a close look at before doing that.

One, the difficulty in closing the cylinder after a cleaning. I've noticed a similar issue with my S&W's that feature the spring loaded yoke retaining screw. To me it seems as if this system requires a couple of opening and closing cycles to seat the yoke fully rearward in the frame. Because of this it's become a habit for me to apply a bit of reaward pressure on the cylinder when I first close the cylinder after field stripping it and fully cleaning it. My suspicion is that sping loaded plunger tip allows the yoke to sit a touch forward in the frame and it's probably simply a matter of my not paying attention to seating if fully to the rear when assembling the yoke in the frame.

Second, the misfires have recently become a common complaint. I have a 2008 vintage 620 and 2009 vintage 610 and both of these guns were shipped with the strain screw fully seated in the frame and good and tight. Last month I purchased a new 625 JM and was surprized to find that the gun was shipped with the strain screw loose by a full 1/2 turn. It also didn't have any locktite applied to it which was another feature that seemed standard on my 620 and 610. Loose strain screws will not stay in position, especially if they don't have any locktite applied to them. Personally, IMO that locktite is NOT necessary and S&W didn't use this goop until recently. However, the strain screw does need to be tighted down fully and snugged up well because this screw is what applies tension to the mainspring. I would suggest that you remove the grip and check to see if the screw at the bottom of the front strap on the grip frame is tightened down fully. If not, tightening it down will solve your misfire problems. NOTE; it's very important that you use a properly fitted screwdriver to do this because you can damage that screw with a poorly fitted screwdriver. If you don't have a fitted screwdriver I would suggest you pay a gunsmith a few bucks to snug it up or order a gunsmiths screwdriver set from a source such as Brownells.

As for the cylinder jamming, that could be an issue with shooting those reloads and I'll warn you to NOT mention shooting reloads to S&W, it will void your warranty. Instead tell them you were shooting Winchester White Box from Walmart because it can cause problems such as this. Ammos that produce a lot of fouling can cause the cylinder to build up enough carbon fouling in the chambers and on the cylinder face to cause the cylinder to "tie up".

This is especially true if your revolver has a Barrel/Cylinder gap that is less than 0.005 inch. I normally check the B/C gap on any new revolver and if I find it's under 0.005 inch I correct it with a bit of careful stoning using a diamond hand lap. My 625 came in with the B/C gap at 0.0025 inch on one side of the barrel extension and 0.005 inch on the other side. It took about 45 minutes of careful work to take down the high spot and it now checks between 0.005 and 0.006 inch. However, I've a lot of experience doing Tool & Die work and have tools and skills most do not. I also have a lifetime of acquiring tools such as Valve shims so taking on a bit of light gunsmithing is something that comes naturally. If you are not of a similar "bent", the safest answer for having a tight B/C gap is to send the gun to the factory to have it corrected.

However, with WWB ammo even a 0.006 inch B/C gap isn't enough to keep the cylinder from tying up. I have an older model 67-1 with a 0.006 B/C gap and it will tie up the cylinder with just 30 or 40 rounds of WWB sent downrange. My hunch is the problem is too much variation in case length and a carbon ring forms in front of the case that actually causes the cylinder to jam when casings shift back after firing or under recoil. My answer has been to avoid shooting this particular ammo in my revolvers. Since a local range is normally well stocked with American Eagle ammunition at only 2 dollars more a box it's become my go to range ammo. Another good clean ammo I've found is Blazer Brass, however I can only find that when visiting my brother in Ohio, for some reason it's just not stocked in my area. BTW, that's Blazer Brass, NOT NOT simple Blazer in the aluminum casings, that Blazer ammo is foul beyond description. In addition the Blazer Lead Round Nose will produce leading in the newer ECM barrels that I feel could lead to a bullet jamming in the barrel, yeah the leading I saw with just one box of Blazer LRN was that bad. Point is, AMMUNITION MATTERS. If you are on a budget, limit your selection to the American Eagle or the Blazer Brass.

Finally, shooting reloads will not only void your warranty it can also blow up your gun. We've seen the results of reloading mistakes often enough on this forum that the universal rule here is to NEVER shoot any reload you didn't produce using your own hands. For all you know those reloads were cooked up by someone "knocking" back a beer or two with each box of ammo produced. If you have any of those reloads left over I would suggest you turn them into a local PD or shooting range for disposal.