Unknown (to me) Premo caliber

I may be retreading here, apologies if so I will move & edit, but I have this in my list of unknowns for some reason.
I believe it's Lavina sourced..anyone know the Lavina designation? And to the gist, anyone know the Gruen/Premo caliber designation? Thanks.

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I believe that’s the 720—the big guy!

I believe that’s the 720—the big guy!

Thanks alot! That's the info I need. 19 ligne, Lavina caliber 23.

Another one id like to eliminate off my list, so I'll piggyback my own post.
Do you know this one? Thanks!

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20230906_125328.jpg (34.36 KiB) Viewed 84 times

whoah, new one maybe for me. any hints on signature? can't read

This is what I got:

My notes; "GRUEN W C? 2?ADJ SWISS 15 JEWELS BREVET51482"

Seller notes; "Rare + Swiss Patent 51482 FHF Robert?8.75"' = 19.8 mm Gruen Watch Movement 15 J"

How accurate any of that is, not sure.

Definitely a rare one!
According to the setting bits I'd say it is a caliber 620/21/26/27 relative. Most likely 620 or 621.

Definitely a rare one!
According to the setting bits I'd say it is a caliber 620/21/26/27 relative. Most likely 620 or 621.

Thanks for your reply, it does look like the intermediate wheel bridge part is a match for 620 series and it's relatives 100, 101.

We know what 100, 101 look like. And the 626 is shown in 1926 supplement B, which means rannfft is correct in this instance of the 626 layout.

http://www.ranfft.de/cgi-bin/bidfun-db. ... &Gruen_626

You're right, chances do seem high this is possibly an image of an actual 620.

Yes, I agree. Should be 620/621. Also, middle bridge is similar to the 131. I have one in the boneyard, took detailed pics 2 years ago of the dial side & dial but neglected to take the obvious pic of the bridges. When I find again, I’ll share, but it too is from before cal # was stamped on the plate.

Unique that it’s Gruen w co (not WSC) and—on this one specifically—the sn appears to line up with the V4 / non-precision (at this time) series. Well, possibly. Contrast vs. cal 615, which is Gruen w co and even Precision, but has a non-Gruen sn.

Funny, reason I didn't recognize the 720 was I thought that particular movement I was showing was under 9 ligne. Context matters.
"Also, middle bridge is similar to the 131"
I need some more info here, please, is 8 3/4 ligne caliber 130/131 made by Font-Robert?