IMR 4227 is a versatile powder originally designed for magnum handguns and small capacity rifle cartridges. This article contains published IMR 4227 reloading data for multiple cartridges to help you find a safe starting point for your loads. Keep in mind that exact data depends heavily on the specific cartridge, bullet weight, components, and the original publishing source.
IMR 4227 Reloading Data
| Cartridge | Bullet Weight (Grs.) | Min Charge (gr) | Max Charge (gr) | Max Velocity (fps) |
| 22 Hornet | 40 | 10.5 | 11.5 | 2,800 |
| 22 Hornet | 45 | 9.7 | 11.4 | 2,700 |
| 221 Fireball | 40 | 16.0 | 17.5 | 3,100 |
| 221 Fireball | 50 | 14.5 | 16.0 | 2,850 |
| 30 Carbine | 110 | 13.0 | 14.5 | 1,850 |
| 300 AAC Blackout | 110 | 17.0 | 18.5 | 2,150 |
| 300 AAC Blackout | 125 | 16.0 | 17.5 | 2,000 |
| 300 AAC Blackout | 150 | 14.5 | 16.2 | 1,850 |
| 357 Magnum | 158 | 13.0 | 15.5 | 1,250 |
| 357 Magnum | 180 | 12.0 | 14.0 | 1,150 |
| 44 Remington Mag | 240 | 20.0 | 22.0 (C) | 1,350 |
| 44 Remington Mag | 265 | 18.5 | 20.5 (C) | 1,250 |
| 45 Colt (Ruger Only) | 250 | 20.0 | 23.5 | 1,200 |
| 454 Casull | 300 | 28.5 | 31.5 | 1,600 |
| 45-70 Govt (Trapdoor) | 300 | 28.0 | 32.0 | 1,450 |
| 45-70 Govt (Trapdoor) | 405 | 24.5 | 27.5 | 1,250 |
Explanation Of The Data
The supplied IMR 4227 load data covers a mix of small rifle cartridges, modern tactical rounds, and large magnum revolvers. The data illustrates how powder charges must be adjusted based on bullet weight, case volume, and firearm action strength.
22 Hornet
The 22 Hornet is a small capacity centerfire where fast burning powders like IMR 4227 excel. For a 40 grain bullet, the powder charge ranges from 10.5 grains to 11.5 grains, reaching a maximum velocity of 2,800 fps. Moving to a slightly heavier 45 grain bullet requires the starting load to drop to 9.7 grains and caps the maximum charge at 11.4 grains, yielding a lower top velocity of 2,700 fps.
300 AAC Blackout
The 300 AAC Blackout utilizes faster burning powders to function properly. For light 110 grain bullets, the required charge spans from 17.0 to 18.5 grains to achieve 2,150 fps. As bullet weight increases to 150 grains, the powder charge decreases to a range of 14.5 to 16.2 grains, generating a maximum velocity of 1,850 fps.
44 Remington Mag
In the 44 Remington Mag, the data shows loads for heavy cast or jacketed bullets. A 240 grain bullet requires 20.0 to 22.0 grains of powder to reach 1,350 fps. For the heavier 265 grain bullet, the charge is reduced to a range of 18.5 to 20.5 grains. The (C) notation indicates a compressed load, meaning the powder fills the case enough that the seated bullet slightly compresses the charge.
45-70 Govt (Trapdoor)
For the 45-70 Government, this specific data is tailored for older, weaker Trapdoor actions. A 300 grain bullet uses 28.0 to 32.0 grains to reach 1,450 fps. Firing a massive 405 grain bullet restricts the powder charge to 24.5 to 27.5 grains, keeping chamber pressure safe for vintage rifles while producing a maximum velocity of 1,250 fps.
Understanding IMR 4227 Load Data
A starting load represents the minimum safe powder charge verified by ballisticians to ensure the bullet exits the barrel without creating dangerous secondary pressure spikes. The maximum published load is the absolute highest charge tested that remains within established SAAMI safety limits. Velocity indicates the speed of the projectile at the muzzle, measured in feet per second (fps). Pressure data measures the internal force generated inside the chamber upon ignition. Bullet weight and barrel length are highly influential variables; heavier bullets require reduced powder charges, and longer test barrels generally produce higher velocity readings. Cartridge overall length (COAL) dictates the seating depth, which directly impacts case volume and pressure. Load data differs between cartridges because internal case dimensions, bullet diameters, and operational pressure thresholds are entirely unique to each caliber.
Manufacturer Data vs Provided Data
The provided table aligns securely with historical published IMR 4227 reloading data found in established manuals and the Hodgdon Reloading Data Center. The notation of a compressed charge (C) in the 44 Remington Mag data correctly reflects standard Hodgdon and IMR formatting. The 22 Hornet data also mirrors known manufacturer limits for 40 grain and 45 grain projectiles. Slight differences in velocity between this table and current online manufacturer data can occur due to variations in primer brand, precise bullet profile, and test barrel length.
IMR 4227 Safety
Reloading data is component specific. You must never substitute bullet profiles, primer brands, or brass manufacturers without consulting reliable published data, as minor changes can drastically alter chamber pressure. Starting and maximum loads must not be confused; always start at the minimum charge and work up slowly. Data for one cartridge cannot be transferred to another cartridge under any circumstances. Always follow published manufacturer data exactly as printed.
FAQs
What is IMR 4227 reloading data?
It is the tested and published specifications for loading IMR 4227 powder into specific cartridges, detailing safe minimum and maximum powder charges and expected velocities.
What cartridges use IMR 4227?
IMR 4227 is widely used in magnum handgun cartridges like the 44 Remington Mag and 357 Magnum, as well as small capacity rifle cartridges like the 22 Hornet and 300 AAC Blackout.
What bullet weights have published IMR 4227 data?
Published IMR 4227 load data covers bullets as light as 40 grains in the 22 Hornet up to heavy 405 grain bullets in the 45-70 Government.
Where can I find an IMR 4227 load data chart?
You can find reliable IMR 4227 load data charts in printed reloading manuals from major bullet manufacturers or online at the Hodgdon Reloading Data Center.
Does Hodgdon publish IMR 4227 data?
Yes, Hodgdon distributes IMR powders and provides comprehensive IMR 4227 reloading data through their official manuals and online data center.
Why does IMR 4227 load data vary by cartridge?
Load data varies because each cartridge has a distinctly different internal case capacity, bullet diameter, and maximum safe pressure limit.
Can IMR 4227 data for one cartridge be used for another cartridge?
No, powder charge weights are perfectly specific to the individual cartridge and bullet combination and cannot be safely transferred to any other caliber.