The short answer
A replica Speedmaster listed as "cal 9300" is a copy of the two counter Speedmaster: one chronograph counter at 3 o'clock that tracks both hours and minutes, running seconds at 9, and a date window. That face comes from Omega's in-house calibre 9300, a different watch from the classic three register moonwatch. No replica has a real 9300 inside. What you get is an Asian automatic chronograph, usually from the 7750 family, or a hand wound Seagull ST19 in cheaper builds, dressed up to imitate the original. The case and dial can get close. The movement can't.
What calibre 9300 really is
Omega's 9300 is an automatic chronograph with a Co-Axial escapement and a silicon balance spring. Two barrels run in series for about 60 hours of reserve. It drives two counters rather than three, with elapsed hours and minutes sharing the counter at 3 o'clock and small seconds at 9. Omega fitted it to 44.25 mm Speedmaster chronographs and to the 41.5 mm Speedmaster '57.
That detail explains the shape. A 9300 Speedmaster is a thick watch with a deep caseback and a crystal that sits high. It wears taller and heavier than the moonwatch most people picture when they hear the name.
Why the calibre name shows up in listings
Sellers use "9300" as shorthand for the dial layout, not as a movement claim. If a listing says 9300 and the watch has three subdials, the listing is wrong. If it has two counters with the chronograph hours and minutes on one dial, the outside is right and the inside is a stand-in. Treat the calibre name as a description of the front of the watch, then judge the movement separately.
What to check before you buy
- Counter layout. Two counters, not three. Chronograph counter at 3, running seconds at 9. Three subdials means a moonwatch case, not a 9300 case.
- Inner hours hand. Start the chronograph, let it run ten minutes, and watch whether the shorter hand in the 3 o'clock counter creeps forward as minutes accumulate. On cheap builds that hand can be decorative.
- Date position. It should sit on the centre line, in line with the 6 o'clock marker, not pushed to one side.
- Thickness. Expect roughly 16 mm including the crystal. A listing quoting 12 mm is describing a different case.
- Pushers. Short, defined travel on start, stop and reset. Mushy pushers, or one that needs a hard shove, point to a cheap chronograph module.
- Reset. Hands should snap to zero and stay there. Drifting hands after a reset are the most common fault on these builds.
- Alignment. Bezel insert, dial and date wheel should all sit on the case centre line. Wide gaps at the lugs show at arm's length.
Movement families and what they mean for you
Most automatic replicas in this case shape use a 7750 derived movement. It winds from the rotor, runs the chronograph, and parts are easy for a watchmaker to source, which matters more than any spec sheet. The trade-offs are thickness and a rotor you can hear in a quiet room.
Hand wound builds centre on the Seagull ST19. It is thinner, the pushers often feel crisper, and you wind it every day. Use the chronograph in short bursts on either movement. Leaving it running all day adds wear and can pull amplitude down until the watch runs slow.
Sizing and daily wear
44.25 mm reads large on a 6.5 inch wrist and settles down at 7.25 inches or more. Check lug to lug, not just diameter. A tall case with long lugs is what makes these watches catch on a cuff. Leather sits lower than a steel bracelet and hides some of the height.
Judging quality tiers
Price tracks three things: case finishing, crystal, and movement. The bottom tier gives you mineral glass, stamped pushers and a rough automatic. Mid tier adds sapphire, cleaner brushing and polishing, and a movement with decent decoration. The top tier gets a closer case profile, correct hand shapes, and a movement a watchmaker will open without complaining. Ask what the crystal is, ask which movement family is inside, and ask for a caseback photo on a scale. Those answers tell you more than any listing copy.
Bottom line
Buy a replica Speedmaster cal 9300 for the two counter dial and the tall case, not for the movement name. Verify counter layout, date position and thickness first. Get those right and the watch reads correctly on the wrist, while the inside stays a known quantity you can keep running.