Robmac

Toolguy, thanks again for good, practical advice. I'm going to try what you suggested. I had generally always stoned with a part against the top of a fixed stone, trying to keep consistent, but doing what you say and setting up stone to surface and using side of stone would obviously help ensure 90 degrees. Great advice, thanks again.

I got the hammer flush to the firing pin area, thanks, but the slight wobble of the hammer still has me miffed...with the hammer all the way forward, against firing pin, as it moves that fraction of an inch back to its resting position, at the last moment it moves slightly to the right (touches the frame a bit, the original problem). To me that means it's starting next pull from there, not good in my opinion. I can repeat it without any springs involved. The last actions to happen are the rebound slide pushing hammer forward, and trigger returning forward with its rear most part coming down to touch the hammer. With the trigger reset (forward), if I push rebound slide forward manually to where it would stop (the bump of rebound slide right under hammer's mating surface), it happens. Also, if I set up hammer and rebound slide first, and then reset trigger, it happens. It's something right there, amongst those three parts. As best I can measure with calipers (not ideal), the three surfaces seem relaitvely uniform on each of their sides, no high spots to cause that jolt as the they mate up, at least not evident enough to cause a perceptible wobble. I'm not about to mess with those areas willy nilly, but I am stumped. I will see how it performs, and put is some shims, but even if it's good, I would love to know cause and remedy. I may have to pay a smith to find out! Thoughts? Thanks.

Toolguy, you were dead on! That crossed my mind about sear/trigger, but I would have sworn I kept the sear's original profile....nope, it was visibly longer on it's left side. As for area where hammer hits firing pin and frame, with factory hammer, the flat part of the hammer ends up flush to frame, no gap. With the Apex hammer however, there is a gap. My gages are too wide side to side to get up in there, but looks to me like 0.010" gap. Should I stone the foremost part of the hammer, the little edge that sits below and in front of the part of the hammer that strikes the firing pin? The goal being I guess to eliminate that gap and let the hammer hit flush? I'll wait to hear back. Huge help, really appreciate it!

Thank you both. I will perform those checks, and will grab some shims. I do visually detect some definite - but very slight - side to side movement of the hammer as it's moving rearward. I'm assuming it's not the pivot pin, because I never had it with the stock hammer, and when I put the stock hammer back in, it does not happen. Odd. Thanks again for the help, I may have a few follow up questions Toolguy. Much appreciated.

The questions ultimately are 1) whether and where a new Apex N frame hammer might need a bit of stoning (besides the sear), and 2) is any peening of frame below firing pin normal...but 1st the background... I put in an Apex hammer in my 627 and I found that I actually needed higher spring tension to get reliable strikes with Federal primers. I then realized that the hammer was hitting the frame on the right side (robbing energy for sure), and I found in turn that the sear pin was not perfectly flush with the left side of the hammer, which probably contributed (I had driven the pin out to fit the sear). Fixed that, but nonetheless, there is still not same clearance between right side of Apex hammer and frame as there is with stock hammer and frame. I can fit a thickness of paper in between the stock parts, but not the Apex. Apex hammer also measures a few thousands thicker in that area. Can I assume it's proper to just stone that corner of the hammer? Secondly though, I notice that inside the frame, about 1/8" directly underneath the firing pin is shiny/ somewhat peened on left side, down below firing pin where that leading edge/ledge of the hammer would strike. It's roughed up for about an 1/8", to the bottom of that part of the frame below firing pin. I can't get a photo file small enough to attach. I never noticed that before, but I also never looked for it. Does anyone know of this is normal? Is it from the sliding hammer block sliding up-and-down, or is it maybe that that leading edge of the hammer needs stoning to interfere less? It just doesn't look right at all, more pronounced than wear in the same area on my 586. Just curious if it should be addressed. Thanks for any insight.