Callaway Big Bertha OS vs Callaway Big Bertha B21
Side-by-side factory specifications. Differing values are highlighted.
Callaway Big Bertha OSinvestment cast · cast stainless steel with Exo-Cage construction, a next-generation 360 Face Cup and a tungsten-loaded internal standing waveCallaway Big Bertha B21cast with an A.I.-designed Flash Face Cup · stainless body with a Flash Face Cup, Visible Tungsten Energy Core and urethane microspheres
Specification comparison
| Club | Big Bertha OS loft | Big Bertha B21 loft | Big Bertha OS lie | Big Bertha B21 lie | Big Bertha OS length | Big Bertha B21 length |
|---|---|---|---|---|---|---|
| 4 | 20.5 | 19 | 60.5 | 60.5 | 39.125 | 38.75 |
| 5 | 23 | 22 | 61.3 | 61.3 | 38.5 | 38.125 |
| 6 | 26 | 25 | 62 | 62 | 37.875 | 37.5 |
| 7 | 30 | 29 | 62.5 | 62.5 | 37.25 | 37 |
| 8 | 34.5 | 33 | 63 | 63 | 36.625 | 36.5 |
| 9 | 39 | 38 | 63.5 | 63.5 | 36 | 36 |
| PW | 44 | 43 | 64 | 64 | 35.75 | 35.75 |
| AW | 49 | 48 | 64 | 64 | 35.5 | 35.5 |
| SW | 54 | 54 | 64 | 64 | 35.25 | 35.25 |
| LW | — | 60 | — | 64 | — | 35 |
Highlighted cells differ between the two sets. Lofts and lies are factory standard.
Lofts compared
- Big Bertha OS
- Big Bertha B21
Which should you choose?
The Big Bertha B21 is the stronger-lofted set — up to 1.5° stronger than the Big Bertha OS on matching clubs. Expect longer carry per numbered iron but a flatter descent angle; gapping at the wedge end is where that shows up.
Both charts are reproduced in full on their own pages: Callaway Big Bertha OS specs and Callaway Big Bertha B21 specs.