Speedmaster Pro 3861 first week observations

I have seen some discussions on other threads about this movement's accuracy, the "dangers" of running the chronograph for long durations, how to know you've got a full wind without over-winding and potentially damaging the watch, and how running the chronograph impacts the running time after a full wind.
I purchased my new moon watch with the 3861 movement on Sunday 8/22 from an AD.
On Monday at around 7:30AM I gave it what I thought was a full wind (in hindsight it very likely wasn't), then at around 10:30AM I decided to start the chronograph and let it run. The movement stopped at around 10:30AM Tuesday morning running approximately 3 seconds fast. Chronograph ran fine with no issues for the entire 24 hours. One interesting note is that I happened to notice within a couple of minutes of when it stopped and then as I was taking it off of my wrist I noticed it started again and ran for about another 10 minutes before stopping.
I waited until noon on Tuesday to give it another full wind and see how long it would run. This time I listened to the "clicks" as I was winding and just kept going until I didn't hear clicks. I also confirmed that my fingers were slipping on the crown by the orientation of the logo on the crown not changing after I was at a full wind mechanical stop. It ran 64 hours and 10 minutes, having stopped at 4:10AM on Friday morning. I noticed what time it had stopped after I woke up, and when I picked it up it started again and ran for about 10 minutes and then stopped. I had checked it at the 24 hour and the 48 hour intervals for accuracy: 3 seconds fast at 24 hours and 5 seconds fast at 48 hours.
On Friday at 8:00AM I gave it a full wind and again confirmed by the absence of "clicks", and the location of the logo on the crown, that I was at a mechanical stop. I also started the chronograph at 8:00AM. As of this moment (8:15AM Sunday) both the chronograph and regular movement are still running. This time though it's running faster than on the previous winds: 2 seconds fast at 12 hours, 4 seconds fast at 24 hours, 6 seconds fast at 36 hours, and 8 seconds fast now at 48 hours.
I will post again this evening or tomorrow with the statistics for this full run with the chronograph moving the entire duration.

Got my 3861 Sandwich on 8/25 (my 1st Speedy)........experiencing the same thing as you and this is what I discovered as I'm running the chrono all the time...........

The chrono needs more torque to run so if you are low in power reserve the watch will stop and restart for a brief time if you somehow nudge the Speedy....my guess is centrifugal force nudges the balance wheel to start again......

Don't baby the winding......I did and I know I was not fully winding her the first few days......was afraid of breaking her (this is my first premium watch)....you know you fully winded her when you can't turn the crown (go slow the first time, but you will know when you can't go no more...you get more comfortable doing it the next time).....

Wind her every 24 hours.....the SA in the OB told me to wind her every other day but it's OK to wind her every day so you can get that full torque if you use the chrono all the time......

This forum has a lot of info.....I been using search a lot and learning more and more every day on this iconic timepiece....hope the above helps and enjoy her in good health......

There really should be a sticky about this, people really overthink the whole winding thing. Omega themselves say to fully wind it every day.

Every morning when you put the watch on (or when you take it off if you prefer), wind it (gently but deliberately) until it hits the obvious mechanical stop. If you don't force it past that stop, then you can't overwind it, that's what it's designed for. There's really nothing more to it than that, yet there are constant threads about people wondering how many rotations they should count and how to know that it's wound properly etc.

I had similar problems with my new 3861. Not being fully wound equaled lack of power reserve, or so you would think. I called SGUS and spoke with a very knowledgeable customer service rep. I was told to wind my watch 60 times and unlike previous manually wound watches, you can not over wind as it will simply stop. Initially 60 winds equalled 60+/- hours of power reserve. I wore my new watch daily and wound it 17 to 20 winds every morning. After a week or so it didn't keep running through the night. I called customer service again and I was told to send them the watch, which I did. A week later they sent me an email saying that there was low amplitude and they ordered the necessary parts to resolve this problem. I was told it should be fixed and ready to return by Sept. 20. Best of all, No charge for the repair or the return shipping. I'll bet they'll have quite a "few" returns.

Obviously news for me, but coming from you, I'll take it as gospel - thanx, Miki

Update on running with the chronograph going: ran for 57 hours and 4 minutes with the chrono "on" the entire time after a full wind; once I noticed that it stopped I hit the chrono "start/stop" button to disengage, and it started up again and ran for another 7 hours and 8 minutes before stopping. So total run time was 64 hours and 12 minutes. (I picked it up and hit the reset button to zero-out the chrono and it started up again and ran another 9 minutes)
I learned a long time ago to not draw conclusions from data sets where n=1, but I'm trying to wrap my head around the fact that when I did not run the chronograph the total run time was 64:10, and when I did engage the chrono and it was consuming energy stored in the spring for 57 hours it still ran for a total of 64:12 (statistically the same as 64:10). Has Omega been unwittingly manufacturing the foundation for the ever-elusive perpetual motion device all these years?
The accuracy on this recent run with the chronograph engaged resulted in consistently running 4 seconds fast per 24 hours.

Summary:
For anyone who's maybe still a little concerned about "over-winding", I'm confident that winding with a "finger-tight" grip on the crown until it hits a mechanical stop and just won't turn any more (you will stop hearing the clicks too) has not caused any damage to my Speedo. This is my first expensive watch (unless you count a $350 Citizen Eco-Drive quartz as "expensive"), and I have no prior experience with a winding or automatic watch, so I'm a total novice at winding and I still didn't screw it up.
Running a "full wind" all the way down without engaging the chronograph resulted in a life or 64:10 and running fast by an average of 2.5 seconds fast per 24 hours.
Running a "full wind" all the way down with the chronograph engaged resulted in a life of 57:04, and then when I hit the chrono start/stop button again it ran for another 7:08 (64:12 total), and running fast an average of 4 seconds per 24 hours.
I'm inside another "full wind" and it's running about 1 second fast after almost 11 hours.
Again, I know better than to draw conclusions from a data set of n=1, but can anyone tell me if it makes sense that the watch would run faster (4 sec / 24 hrs fast) with the chronograph running than without the chrono running (2.5 sec / 24 hrs)?

Because my hard-earned $6K gave me the right, ...and seriously nope, but there wasn't a real-world need to travel to the moon 52 years ago either, but look how much fun that has provided for us!

It has been 4 weeks now that I have owned my Speedmaster. I have worn it exclusively most days except for my swimming workouts where I sport my Citizen 200m Diver (probably not a hugely popular brand here, but I really like Citizen - I will post a new thread soon explaining why, ...even at the risk of generating little to no interest). But back to my 2021 Speedmaster Pro with a 3861 under the hood, black & white interior, and hesalite windshield. Every time I wind, I make sure to complete a full wind continuing until I reach the mechanical stop. For me that's typically 70 to 75 winds after the main spring has completely run-down and the watch has stopped, or around 60 when winding every other day, or 30 when winding every day; ...regardless of the number of winds though, I always just go until I reach the mechanical stop. I have tried all of the above as far as frequency of winding goes, and I have not noticed winding frequency impacting accuracy. I have noticed though that the less I wear the watch the more it seems to be on the plus side of inaccuracy. I have found that it's been ranging from +2sec/24hrs to +4sec/24hrs, with the +2sec/24hrs on the days when it's on my wrist for more hours and I'm doing more activity. When I'm not wearing it, I have stored it face-up every time. The Master Chronograph designation requires an accuracy of 0 to +5sec/24hrs, so my Speedo is pretty-much running dead-nuts centered nominal on that.
Anyone know why they set the METAS certification range to 0/+5 instead of say -2/+3 so the centered nominal would be closer to zero?

I’m no expert but would imagine it’s because you never want your watch to run slow, in case you miss an important meeting or some such. Running a bit fast would mean that you would always turn up early. At -2 you would likely be a minute late if you had not adjusted it at all over the previous month 😲 😉

...reminds me of the old "I Love Lucy" re-run where she sets the clock back 1 hour to give herself and extra hour to get ready for the dinner party

Just got off the phone with SGUS in Syracuse, NY. My new 3861 that I returned for lack of power reserve that was originally scheduled to be returned from service today. It has now been delayed until Oct.12, due to lack of parts.
Considering they received my watch July 7 that makes for a 3 month turn around. Just think if it went to Geneva 🙁