Reloading precision for the 38-40 caliber family starts with verified data that matches your firearm, bullet choice, and shooting goals. Carefully recorded 38-40 reloading data helps you balance accuracy, velocity, and safety every time you load.
Below is a detailed reference table that organizes key load metrics for common 38-40 factory loads. Use this as a quick scan before selecting powders, primers, and bullets for your specific build.
| Bullet Weight | Case Volume | Recommended Powder | Optimal Velocity |
|---|---|---|---|
| 130 gr | 22.5 gr H2O | Hodgdon H4227 | 1200 fps |
| 140 gr | 23.8 gr H2O | IMR 4227 | 1250 fps |
| 150 gr | 24.9 gr H2O | Varget | 1300 fps |
| 160 gr | 26.3 gr H2O | Reloder 15 | 1280 fps |
Understanding 38-40 Cartridge Dimensions
The 38-40 Winchester traces back to 1884 and remains a popular medium-bore choice for deer and defense. Knowing exact case dimensions, shoulder angle, and chamber specifications is essential for safe loading and consistent accuracy.
Use a chamber and headspace gauge before adopting data from other cartridges, because dimensional variations can change pressure signs. Respect the published maximums and always start at the low end when testing new combinations.
Selecting the Right Powder for 38-40 Loads
Choosing the correct powder directly influences velocity, pressure, and group size. Medium-slow powders typically work best, giving clean ignition and manageable recoil in older lever actions.
Key considerations when picking powder
- Check burn rate charts against your barrel length.
- Match powder capacity to the bullet weight and seating depth.
- Prefer powders with consistent metering characteristics for repeatable loads.
Primer Choice and Ignition Reliability
For the 38-40, a small rifle primer is standard and generally delivers dependable ignition. Some reloaders experiment with magnum primers in long, skinny cases, but this can raise pressure and should only be done with published data.
Maintain clean primer pockets and use a primer seating tool that centers the primer to avoid off-angle ignition and misfires. Consistent primer seating depth helps maintain uniform shot-to-shot performance.
Bullet Seating Depth and Accuracy Tuning
Seating depth affects ogive alignment with the rifling, which has a big impact on point of impact and velocity. For the 38-40, many shooters seat bullets to touch the rifling with minimal COAL for best accuracy.
Use a case lubricant and resize consistently to ensure smooth chambering, especially in tubular magazines. Record every seating trial so you can trace changes in groups and pressure signs across different setups.
Core Reloading Practices for 38-40 Shooters
- Always start at the minimum load and increase in small, documented steps.
- Use a chronograph to measure velocity and watch for spikes that indicate pressure issues.
- Inspect every case for cracks, fired primer pockets, and case stretch before reloading.
- Keep detailed records of powders, primers, seating depth, and group sizes for each load.
- Verify chamber dimensions and headspace before adopting hot or experimental loads.
FAQ
Reader questions
How can I safely increase velocity without exceeding safe pressure in my 38-40 loads?
Start by consulting current reloading manuals for updated data, then make tiny increments while watching for pressure signs like stiff extraction or unusual primer flow. Confirm velocity with a chronograph and inspect cases for uniform firing pin marks before long sessions.
Is it safe to use data from similar cartridges like the 32-20 for my 38-40 load development?
Never apply data from other cartridges directly, because case capacity, wall thickness, and throat geometry differ. Use only published 38-40 data and treat any cross-reference as an informational starting point, not a loading manual.
What is the ideal COAL for a 150 gr bullet in a 38-40 load tuned for a tubular magazine?
For tubular magazines, a COAL around 2.100 to 2.180 inches often works well with a 150 gr flat-point bullet, but always verify with your gun’s magazine and throat. Prioritize reliable feeding and safe pressure over shaving length for maximum accuracy. Use a fresh, high-quality small rifle primer and ream primer pockets if they show stretching or firing overpressure signs. Consistent primer seating and clean pockets reduce misfires and support uniform ignition across multiple reloads.