For 9mm ammunition, you should use *small pistol primers*. Here are some specific recommendations and considerations:

### Primer Type
- *Small Pistol Primer*: This is the standard primer used for reloading 9mm ammo. Brands like CCI, Federal, Winchester, and Remington all produce reliable small pistol primers.

### Variations
- *Standard vs. Magnum*:
- *Standard Small Pistol Primers* are generally sufficient for most 9mm loads.
- *Small Magnum Pistol Primers* can be used if you are loading a high-velocity round or using slower-burning powders that may require a bit more ignition energy.

### Brand Considerations
- Consider reputable brands known for quality and reliability. Some popular options include:
- *CCI 500*: A common choice for standard loads.
- *Federal 100*: Known for consistent performance.
- *Winchester WSP*: Another reliable small pistol primer option.

### Check Reloading Manuals
Always refer to a reliable reloading manual or guide, as they provide specific recommendations based on your powder and load to ensure optimal performance.

### Conclusion
For 9mm ammunition, stick to small pistol primers, and consider the specific characteristics of your loads when choosing between standard reloder 7 and magnum primers. Make sure to follow all safety guidelines during the reloading process.