I am in the process to zeroing in my 620.
The shots won't go into the center. The groups are tight but still off center @ 4 o'clock out to the 7th ring even from 15 feet.
Almost seems like a magnet pulling the shots off center.

I tweaked the rear sight already 4 clicks to the left and 1 click up.

I never had to adjust the sights on any of my revolvers, they all shoot sharp since I took them out of the box.

Do I need to tweak the sights more or could there be an issue with the barrel assembly?

I am in the process to zeroing in my 620.
The shots won't go into the center. The groups are tight but still off center @ 4 o'clock out to the 7th ring even from 15 feet.
Almost seems like a magnet pulling the shots off center.

I tweaked the rear sight already 4 clicks to the left and 1 click up.

I never had to adjust the sights on any of my revolvers, they all shoot sharp since I took them out of the box.

Do I need to tweak the sights more or could there be an issue with the barrel assembly?

I'd keep cranking on those sights! Sometimes, just shooting on a blank piece of paper (about 12" square) helps to center zero a gun.

Just to rule everything out, have you had someone else try the firearm? A shooting buddy, Range Officer, Instructor, etc?

If they get the same results, keep adjusting the sights.

__________________
"Acta non verba"

I don't know whether this gun is new or used, but if it's used, have you verified that the rear sight actually MOVES when you turn the windage screw? It could be broken.

The elevation screw gives you a VERY fine adjustment with each click. An adjustment of only 1 click won't be readily apparent at such short range. In this case, I would advise adjusting it more. FWIW my preferred way of adjusting S&W sights is to purposefully overdo the adjustment- I'll shoot a group, turn the screw 5-6 times while counting the clicks carefully, then shoot another group, and use its new position to calculate how far the POI moves per click. As a rough example, let's say the revolver groups 4" right of the bullseye. I adjust it 6 clicks to the left and now it shoots 2" left. I calculate that the POI moves 1" per click. (A real S&W would move less than this at short range.) I now know that if I move the sight 2 clicks to the right, all will be well.

+1

I'd also suggest even a slow fire bulls eye target at 15 feet is way too big a target? At 5 yards I'd be more likely to use some of those 1 inch diameter orange peel and sticks on a blank sheet of paper, or the back side of a target. That close, it may take a lot of movement to correct? I'd seriously consider putting the gun using the same ammo, distance and target type, in the hands of two other known quality shooters, to see if they land at the same POI for all three of you, pre-adjustment?

Thank you for the suggestions. I will continue to work on it. It's a great handy revolver. I considered it as a possible carry gun, but for that matter she needs to be exquisitly spot on.

I bought the 620 as new, but curiously enough, I had the impression, it's been shot before. Could have been a display item. There is something about the 620. I think she is fantastic in construction for a 4" 357 with +1 round, but at the same time I come across considerable sceptic reviews as well.

The target is 7" in diameter. The groups average 2 1/4" from the bulls eye.

I was under the impression, that from this close of a distance the POI would move noticable quicker.

I also will maintain a more consistent rested position, the next time I take it to the test.

An other shooter always helps, provided he comes with experience.

Thanks again.

I currently have 5 Smith revolvers with adjustable sights. Three of them shot to point of aim right out of the box and I've never touched their sights. The other two required at least a little tweaking. My most recent acquisition is a 66 no-dash which was sold to me as "unfired" but which, judging from the carbon rings around the cylinders, had been fired at least a couple of times before I acquired it. In my first session I found every round going to the five o'clock position. Tiny groups, overlapping holes, but still, all down and to the right. I asked my wife to shoot a couple of cylinders. She's an excellent shot. Same result. So, I cranked the rear sights up a full turn of the adjustment screw and gave 'em a similar full turn to the left. Bingo! Now, everything hits right at point of aim.

I wondered to myself whether the barrel was misaligned. It sure doesn't look that way, to my eye, everything lines up perfectly. In some light the front sight looks as if it was mounted maybe a millimeter to the right of center of the barrel rib. But, at other times it looks perfectly centered.

My guess is that, if anything was misaligned, it was probably the rear sights. They could have been mounted a tiny bit off center and they certainly weren't zeroed at the factory. But, in the final analysis I don't care because the gun now shoots beautifully.

I've had a similar experience with another Smith revolver that I purchased recently, a 17-5. That gun, at 25 yards, shot about a foot high. I just cranked the rear sights down about one and one-half full turns and now, it's zeroed nicely.