IMR 4198 is a fast burning extruded smokeless rifle powder produced under the Hodgdon brand umbrella. Reliable IMR 4198 reloading data can be found directly from major component manufacturers including Hodgdon, Sierra, Barnes, and Hornady.Handloaders must match IMR 4198 load data to the exact cartridge, bullet weight, and brass specified by the publisher because pressure scales uniquely with each component combination. It is frequently used for small capacity centerfire cartridges and large bore straight wall cases, making it an excellent choice for varmint and brush hunting loads. Some of the most popular cartridges with published IMR 4198 data include the .223 Remington, 7.62x39mm, and .45-70 Government. Always consult primary publishers for the most up to date safety limits before assembling any ammunition.
IMR 4198 Reloading Data
| Cartridge | Bullet Weight & Type | Min Charge (gr) | Max Charge (gr) | Max Velocity (fps) |
| .17 Remington | 20 gr V-MAX | 19.0 | 21.2 | 4,050 |
| .17 Remington | 25 gr Hollow Point | 17.5 | 19.5 | 3,750 |
| .204 Ruger | 32 gr V-MAX | 22.0 | 24.5 | 3,950 |
| .204 Ruger | 40 gr V-MAX | 20.5 | 22.8 | 3,600 |
| .221 Fireball | 40 gr Spitzer | 16.5 | 18.5 | 3,150 |
| .222 Remington | 50 gr Spitzer | 18.5 | 20.5 | 3,100 |
| .222 Remington | 55 gr Spitzer | 17.5 | 19.5 | 2,950 |
| .223 Remington | 50 gr Spitzer | 20.0 | 22.2 | 3,250 |
| .223 Remington | 55 gr FMJ-BT | 19.5 | 21.5 | 3,100 |
| .223 Remington | 62 gr FMJ-BT | 18.5 | 20.5 | 2,900 |
| 6 x 45mm (6mm-223) | 70 gr Spitzer | 21.0 | 23.5 | 2,950 |
| 6 x 45mm (6mm-223) | 85 gr Spitzer | 19.5 | 21.5 | 2,700 |
| .300 AAC Blackout | 110 gr V-MAX | 17.5 | 19.0 | 2,250 |
| .300 AAC Blackout | 125 gr SST | 16.5 | 18.0 | 2,050 |
| .300 AAC Blackout | 150 gr FMJ-BT | 15.0 | 16.5 | 1,850 |
| .300 AAC Blackout | 208 gr A-MAX (Sub) | 10.5 | 11.5 | 1,050 |
| .300 AAC Blackout | 220 gr SMK (Sub) | 10.0 | 11.2 | 1,020 |
| .30-30 Winchester | 130 gr Flat Nose | 27.0 | 29.5 | 2,400 |
| .444 Marlin | 240 gr JHP | 42.0 | 46.5 | 2,250 |
| .45-70 Govt (Trapdoor) | 405 gr Cast Lead | 27.0 | 31.5 | 1,350 |
| .45-70 Govt (Modern) | 300 gr JHP | 44.0 | 47.5 | 2,000 |
Other researched data
| Cartridge | Bullet | Bullet Weight | Published Starting Load | Published Maximum Load | Published Velocity | Barrel Length | Source |
| .223 Remington | Sierra Hornet | 40 gr | 21.5 gr | 23.5 gr | 3200 to 3600 fps | 24 in | Sierra Manual |
| .223 Remington | Speer Semi-Spitzer | 70 gr | 18.5 gr | 20.5 gr | Not Published | 18.5 in | Speer Manual |
| 7.62x39mm | Speer SP | 125 gr | 22.6 gr | 24.0 gr | 2035 to 2250 fps | 24 in | Hodgdon Reloading Data |
| .45-70 Government | Barnes TSX FN | 300 gr | 49.0 gr | 54.0 gr | 2319 to 2500+ fps | 24 in | Barnes Bullets |
What Is IMR 4198?
IMR 4198 is an extruded, single base smokeless propellant originally developed for centerfire rifle cartridges. It sits in the fast burning rate category, making it highly effective for cartridges that feature a small case capacity or large straight cylindrical walls. The powder grains are cut into small cylindrical sticks. While extruded powders do not always meter as smoothly as spherical powders in a mechanical measure, IMR 4198 powder is highly regarded for its consistent ignition and predictable pressure curves. It appears in published data for dozens of cartridges because it provides excellent case fill density and optimal velocities for popular varmint and short range hunting rounds.
Cartridges With Published IMR 4198 Data
Reputable publishers provide current IMR 4198 reload data for a vast selection of mainstream rifle cartridges. Handloaders must note that component differences within these cartridges inherently change the allowable powder charges.
.223 Remington
This is one of the most thoroughly documented cartridges for IMR 4198 reloading.Published data is widely available for bullet weights ranging from 40 grains up to 70 grains.It is a classic application for varmint hunting loads, where the powder yields highly consistent velocities in bolt action rifles.
7.62x39mm
This powder is an excellent choice for the 7.62x39mm when paired with 125 grain bullets.Hodgdon publishes data for this combination using Speer soft point projectiles. Differences in bullet bearing surface mean that data cannot be swapped between different bullet brands.
.45-70 Government
In large straight wall cases, this powder burn rate is used for both lightweight and heavy bullets. Barnes and Hornady publish data for 250 grain to 400 grain bullets in the .45-70 Government. Ammunition loaded for modern strong actions like the Ruger No. 1 will use significantly higher powder charges than trapdoor rifles.
IMR 4198 Reloading Data By Cartridge
.223 Remington
| Bullet | Bullet Weight | IMR 4198 Published Starting Load | IMR 4198 Published Maximum Load | Published Velocity | Barrel Length | Source |
| Sierra Hornet | 40 gr | 21.5 gr | 23.5 gr | 3200 to 3600 fps | 24 in | Sierra Manual |
| Speer Semi-Spitzer | 70 gr | 18.5 gr | 20.5 gr | Not Published | 18.5 in | Speer Manual |
7.62x39mm
| Bullet | Bullet Weight | IMR 4198 Published Starting Load | IMR 4198 Published Maximum Load | Published Velocity | Barrel Length | Source |
| Speer SP | 125 gr | 22.6 gr | 24.0 gr | 2035 to 2250 fps | 24 in | Hodgdon Reloading Data |
.45-70 Government
| Bullet | Bullet Weight | IMR 4198 Published Starting Load | IMR 4198 Published Maximum Load | Published Velocity | Barrel Length | Source |
| Barnes TSX FN | 300 gr | 49.0 gr | 54.0 gr | 2319 to 2500+ fps | 24 in | Barnes Bullets |
Understanding IMR 4198 Load Data
Reading a published IMR 4198 load data chart requires strict attention to multiple variables. The starting load represents the lowest safe powder charge recommended by the ballistic laboratory. The maximum published load is the absolute upper limit tested by the manufacturer before pressures exceed standard limits set by SAAMI. Velocity indicates the speed of the bullet as measured in feet per second during the laboratory test. Pressure figures are sometimes provided in PSI or CUP to show exactly how close the load is to the safety ceiling.
Every manual also specifies the exact bullet weight and the barrel length used for testing.The cartridge overall length is published to ensure the bullet is seated to the exact depth used by the ballistic technicians.Load data differs between sources because different laboratories use different lots of powder, different brass cases, and different test barrels.
Bullet Weight And IMR 4198 Data
Published IMR 4198 load recipes change significantly depending on the weight of the bullet. As a general ballistic rule, heavier bullets take up more case volume and create more resistance as they engage the rifling, which increases chamber pressure. Consequently, an IMR 4198 powder charge must be reduced as bullet weight increases.
For example, in the .223 Remington, this powder is commonly matched with 40 grain, 55 grain, and 70 grain bullets.A powder charge deemed safe for a 40 grain bullet might cause a catastrophic overpressure event if loaded directly behind a 70 grain bullet.A powder charge published for one bullet cannot automatically be applied to another bullet, even if they share the identical weight, due to differences in bearing surface and jacket material.
IMR 4198 Velocity
Velocity expectations change drastically depending on the case capacity and bore diameter of the cartridge. According to the Sierra Manual, a 40 grain bullet fired from a .223 Remington with a maximum load of 23.5 grains of IMR 4198 achieves a published velocity of 3600 fps from a 24 inch barrel. In contrast, a heavier 125 grain bullet fired from a 7.62x39mm with 24.0 grains of IMR 4198 reaches 2250 fps from a 24 inch barrel.
Barnes Bullets demonstrates that pushing a massive 300 grain TSX FN bullet in the .45-70 Government case requires up to 54.0 grains of IMR 4198 to reach maximum pressure limits in a Ruger No. 1 test barrel. Do not treat the velocity of one cartridge as representative of another.
Barrel Length And IMR 4198 Velocity
Barrel length has a direct impact on the final velocity of any IMR 4198 load.The powder needs time and space to burn and push the projectile down the bore. When a barrel is shorter than the laboratory test barrel, the bullet will exit before the expanding gases can fully accelerate it, resulting in a lower actual muzzle velocity.
The numerical velocity figures published by Sierra and Hodgdon for the .223 Remington and 7.62x39mm were recorded using 24 inch test barrels.A hunter using a 16 inch carbine barrel will not see the same velocities printed in the manual.The test barrel must always be identified to provide accurate context for the published velocity.
Manufacturer Data vs Independent Testing
There is a stark difference between official manufacturer published load data and independent chronograph testing. Manufacturer data is developed in highly controlled ballistic laboratories using universal receivers and piezo electronic pressure sensors. This ensures that the published powder charges remain strictly within safe pressure specifications.
Independent chronograph testing and user submitted load reports are gathered in the field using consumer firearms. Ballistic calculator estimates are generated by software algorithms rather than live firing. Independently measured results often differ from published figures due to variations in chamber dimensions, ambient temperature, and specific powder lots. Reloaders must always give priority to official, pressure tested manufacturer data.
IMR 4198 Pressure And Safety
Following published IMR 4198 data exactly is a fundamental safety requirement. Starting loads are provided for a reason; working up slowly allows the handloader to monitor their specific firearm for pressure signs. Maximum published loads must never be exceeded under any circumstances.
Pressure specifications can spike dangerously if any single component is altered. Bullet substitutions change the friction profile within the bore. Brass differences alter internal case capacity, meaning military brass often requires reduced powder charges compared to commercial brass. Primer differences can also shift the ignition intensity. Seating a bullet deeper than the specified cartridge overall length decreases internal volume and heavily increases pressure. Furthermore, powder lot variation and extreme ambient temperatures can cause a previously safe load to become dangerous. Never attempt to develop an unpublished recipe or exceed the maximums printed in official manuals.
Best Sources For IMR 4198 Reloading Data
The strongest current sources for verified IMR 4198 reloading data are the component manufacturers themselves.
- Hodgdon Reloading Data Center:As the distributor of IMR powders, Hodgdon provides the most authoritative and comprehensive data.Their online center is constantly updated and rigorously pressure tested.
- Sierra Bullets:Sierra offers extensive data for target and varmint applications, breaking down powder charges into clear, incremental velocity tiers.
- Hornady:IMR 4198 load data Hornady publishes covers an immense variety of proprietary bullets across all major calibers.
- Barnes Bullets: Barnes provides excellent data specifically tailored to solid copper monolithic bullets, which generate different friction and pressures than traditional lead core bullets.
- Speer Bullets:The Speer manual provides thoroughly tested loads specifically designed for their proprietary projectile designs.
Official manufacturer manuals distinguish themselves from secondary sources by adhering strictly to SAAMI pressure guidelines.
FAQs
Where can I find IMR 4198 reloading data?
Reliable data can be found in printed reloading manuals and official online databases published by Hodgdon, Sierra, Hornady, Speer, and Barnes.
What cartridges use IMR 4198?
Popular cartridges that utilize this powder include the .223 Remington, 7.62x39mm, .30-30 Winchester, and .45-70 Government.
What bullet weights have published IMR 4198 data?
Published data covers a wide range of bullet weights depending on the cartridge, such as 40 grain bullets for the .223 Remington and 300 grain bullets for the .45-70 Government.
Does Hodgdon publish IMR 4198 data?
Yes, Hodgdon operates the primary online data center for all IMR powders, providing extensive pressure tested load recipes.
Does IMR publish load data for IMR 4198?
IMR powder data is currently managed and published by Hodgdon, which owns the distribution rights to the IMR powder brand.
Why does IMR 4198 load data vary between cartridges?
Every cartridge has a completely different internal case volume and bore diameter, which changes how the burning powder expands and generates pressure.
Does barrel length affect IMR 4198 velocity?
Yes, shorter barrels provide less time for the powder gases to accelerate the bullet, resulting in lower velocities compared to longer laboratory test barrels.
Can IMR 4198 data be used with different bullets?
No, data is specific to the exact bullet brand and profile tested, as variations in bearing surface and jacket material directly affect chamber pressure.
What is the difference between starting and maximum IMR 4198 load data?
The starting load is the lowest recommended charge for safe ignition and baseline pressure, while the maximum load is the absolute highest charge tested before exceeding safety limits.
Where can I find pressure-tested IMR 4198 data?
Pressure tested data is strictly found in the official loading manuals published by ammunition and component manufacturers, which use laboratory equipment to measure exact PSI or CUP.