Conformity of the most common calibers of the world
| mm | in | |
| RF | USA | Great Britain |
| 5.6 | .22 | .220 |
| 5.56 | .223 | .223 |
| 6.35 | .25 | .250 |
| 7.0 | .28 | .280 |
| 7.62, 7.76 | .30 | .300 |
| 7.7 | – | .303 |
| 7.65 | .32 | .320 |
| 9.0 | .35 | .350 |
| 9.07 | .357 | .357 |
| 9.3 | .36 | .366 |
| 10.0 | .40, .41 | .400, .410 |
| 11.0 | .44 | .440 |
| 11.43 | .45 | .450 |
| 12.7 | .50 | .500 |
