Accurate No. 11FS represents a modern pinnacle in the evolution of double-base spherical propellants, specifically engineered to bridge the gap between heavy magnum handgun applications and small-bore rifle cartridges. Developed by Western Powders and now part of the Hodgdon portfolio, Accurate No. 11FS was designed to address a specific tactical and hunting requirement: high-velocity performance coupled with integrated flash suppression. The “FS” in its nomenclature stands for Flash Suppressed, a critical feature for shooters operating in low-light conditions where muzzle flash can compromise night vision or reveal a shooter’s position.
In the contemporary reloading landscape, Accurate No. 11FS has carved out a significant niche, particularly among enthusiasts of the 300 Blackout and large-frame magnum revolvers. It sits in a burn rate neighborhood occupied by legendary propellants, yet it offers a chemical profile that prioritizes cleanliness and signature reduction without sacrificing the high loading densities required for maximum terminal energy. This guide provides a deep technical dive into the properties, applications, and loading characteristics of Accurate No. 11FS.
Executive Summary
- Main Application – High-velocity 300 Blackout supersonic loads and magnum handgun cartridges.
- Key Advantage – Superior flash suppression and exceptional metering consistency.
- Burn Rate Position – Slow-burning handgun / Very fast-burning rifle propellant.
- What This Guide Covers – Technical specifications, temperature behavior, comparative analysis, and cartridge-specific optimization.
Best For: Tactical shooters and handgun hunters requiring high-velocity performance with minimal muzzle signature.
Powder Description & Technical Profile
Accurate No. 11FS is a double-base, spherical powder characterized by its high nitroglycerin content, which provides the high energy density necessary to push heavy projectiles at competitive velocities. As a spherical (or “ball”) powder, the physical geometry consists of very small, uniform rounds that have been treated with specific deterrents to control the burn rate. This physical structure is what allows Accurate No. 11FS to achieve its high gravimetric density, ensuring that even in smaller cases, the reloader can achieve a high percentage of case fill, which is often a prerequisite for internal ballistic consistency.
The chemical composition includes a proprietary flash-suppressant additive. While many older magnum powders produce a significant “fireball” due to unburnt gases igniting upon contact with atmospheric oxygen, Accurate No. 11FS chemically interrupts this secondary combustion. This makes it a premier choice for self-defense applications in short-barreled rifles or hunting revolvers used during the dawn and dusk transitions. Furthermore, the double-base nature of Accurate No. 11FS ensures that it remains relatively easy to ignite, provided that the appropriate primer is utilized to overcome the initial resistance of the deterrent coatings.
Pros & Cons
- Pro – Exceptional flash suppression for low-light shooting.
- Pro – Flow behavior is flawless in both mechanical and digital measures.
- Pro – High energy density allows for maximum velocities in 300 Blackout supersonic loads.
- Pro – Clean burning at the upper end of its pressure range.
- Con – Requires high-pressure levels to achieve full combustion efficiency.
- Con – Spherical geometry can lead to “leaking” in loosely fitted mechanical powder measures.
- Con – Generally requires magnum primers for consistent ignition in cold weather.
Technical Characteristics
The physical and chemical properties of Accurate No. 11FS are optimized for high-pressure environments. Its density is a standout feature, allowing it to fit into compressed or near-compressed loads where more voluminous extruded powders would reach their physical limits.
| Feature | Specification |
| Manufacturer | Accurate (Hodgdon Powder Company) |
| Powder Type | Double-Base |
| Grain Shape | Spherical (Ball) |
| Base Type | Nitroglycerin / Nitrocellulose |
| Relative Burn Rate Category | Slow Handgun / Ultra-Fast Rifle |
| Density (g/cc) | 0.985 |
| Primary Feature | Integrated Flash Suppression |
The density of Accurate No. 11FS is approximately 0.985 grams per cubic centimeter, making it one of the denser powders in the Accurate line. This density is a double-edged sword; while it allows for excellent case fill, it also means that even small adjustments in charge weight can lead to significant shifts in pressure. Reloaders should always use a high-quality scale, such as the Frankford Arsenal Platinum Series Precision Digital Powder Scale with case, to ensure charge-to-charge consistency.
Temperature Stability & Burn Rate Analysis
In terms of burn speed, Accurate No. 11FS is positioned just slightly slower than Accurate No. 9 and is very similar in performance to Accurate 4100. On the global burn rate chart, it sits in the same general area as Hodgdon H110 and Winchester 296. This specific speed is critical for magnum handguns because it allows the pressure to stay behind the bullet longer as it travels down the barrel, resulting in higher muzzle velocities than faster pistol powders like Accurate No. 5 could safely achieve.
Temperature stability for Accurate No. 11FS is considered good for a double-base spherical powder, though it does not quite reach the extreme stability of modern “Extreme” line extruded powders. In testing, Accurate No. 11FS shows less velocity deviation across a 0-125 degree Fahrenheit range than older formulations like Alliant 2400. However, it is more sensitive to temperature than a benchmark stable powder like Hodgdon Varget. For most hunting and tactical applications, the velocity shifts are negligible within standard operating temperatures, but long-range shooters using it in 300 Blackout should verify their drops in extreme cold.
Powder Comparison – 4-Way Analysis
When selecting a powder in this burn rate class, shooters often compare Accurate No. 11FS against other industry staples. The primary difference is almost always the flash suppression and the specific pressure curve generated by the Accurate deterrent package.
| Powder | Relative Burn Rate | Density | Primary Cartridges |
| Accurate No. 11FS | Standard (Subject) | 0.985 | 300 Blackout, 357 Magnum |
| Hodgdon H110 | Slightly Slower | 1.050 | 44 Magnum, 454 Casull |
| Accurate No. 9 | Slightly Faster | 0.950 | 357 Sig, 10mm Auto |
| Alliant 2400 | Slightly Faster | 0.840 | 357 Magnum, 44 Special |
While Hodgdon H110 is often the velocity king for magnum handguns, Accurate No. 11FS provides a more versatile pressure profile that works better in the slightly lower-pressure environment of the 300 Blackout. Compared to Alliant 2400, Accurate No. 11FS meters far more consistently in progressive presses. Accurate No. 9 is a better choice for shorter barrels or smaller magnum cases where Accurate No. 11FS might not reach full combustion before the bullet exits the muzzle.
Performance, Metering & Equipment
One of the most praised attributes of Accurate No. 11FS is its physical behavior in reloading equipment. Because the grains are so small and uniform, they act almost like a liquid. When used with a high-quality measure such as the Hornady Lock-N-Load Bench Rest Powder Measure, the charge weights typically vary by less than 0.1 grains. This level of precision is vital for maintaining low standard deviations in velocity, which translates to better accuracy at distance.
However, the fine grain size of Accurate No. 11FS requires equipment with tight tolerances. In some older or budget-oriented powder measures, the “dust” of the powder can migrate between the drum and the housing, causing the measure to bind or leak. For high-volume reloading on a progressive press like the Dillon XL 750, users should ensure the powder bar is properly adjusted to prevent migration. When using automated dispensers like the RCBS ChargeMaster Supreme Digital Powder Scale and Dispenser, Accurate No. 11FS flows exceptionally well and rarely causes the “over-throws” common with large-grained extruded powders.
Recommended Cartridges and Applications
While Accurate No. 11FS is versatile, it truly shines in three specific areas: 300 Blackout supersonic loads, heavy-bullet 357 Magnum hunting loads, and large-bore revolvers like the 44 Magnum.
| Cartridge | Primary Application |
| 300 Blackout | Supersonic Hunting & Tactical |
| 357 Magnum | Heavy Bullet Silhouette & Hunting |
| 44 Magnum | General Magnum Performance |
| 30 Carbine | Service Rifle Competition |
| 454 Casull | Dangerous Game Hunting |
| 460 S&W Magnum | Long-Range Handgun Hunting |
In the 300 Blackout, Accurate No. 11FS is optimized for bullet weights between 110 and 125 grains. It provides the gas volume necessary to cycle the action of an AR-15 reliably while maintaining impressive velocities from short barrels. In magnum handguns, Accurate No. 11FS is best used with heavier-than-standard projectiles, as the increased sectional density helps build the start-pressure required for a complete, clean burn of the double-base propellant.
Bullets
Pairing the right bullet with Accurate No. 11FS is essential for balancing velocity and pressure. Since this powder is on the slower end of the handgun spectrum, it prefers bullets with more “bearing surface” to help build pressure.
| Bullet Model | Weight Range | Recommended Application |
| Hornady V-Max | 110 grain | 300 Blackout Varmint |
| Barnes TSX | 110-120 grain | 300 Blackout Hunting |
| Nosler Partition | 158-180 grain | 357 Magnum Hunting |
| Sierra MatchKing | 125 grain | 300 Blackout Target |
| Barnes TTSX | 225 grain | 44 Magnum Hunting |
When loading for the 300 Blackout, the 110-grain Hornady V-Max is a classic pairing with Accurate No. 11FS, offering explosive terminal performance. For those focusing on big game, the Nosler Partition in a 357 Magnum provides the structural integrity needed to withstand the high impact velocities this powder can generate.
Primers – The 7-10 Rule
Ignition is the most critical safety factor when using high-density spherical powders like Accurate No. 11FS. These powders are coated with deterrents that regulate the burn, and a weak primer may fail to ignite the charge consistently, leading to “hangfires” or erratic pressures. For handgun applications, a magnum primer is almost always recommended. For rifle applications like the 300 Blackout, a “hard” small rifle primer is preferred to prevent slam-fires in semi-automatic actions and to provide the necessary heat for ignition.
Recommended Primers for Accurate No. 11FS:
- CCI 450 (Small Rifle Magnum) – Excellent for 300 Blackout.
- CCI 550 (Small Pistol Magnum) – Standard for 357 Magnum.
- Winchester WSPM (Small Pistol Magnum) – High heat for cold weather.
- Federal 200 (Small Pistol Magnum) – Reliable ignition in all conditions.
- Remington 7-1/2 (Small Rifle Bench Rest) – Very hot, great for 300 Blackout.
- CCI 400 (Small Rifle) – Use only in mild conditions for rifle loads.
- Winchester WLR (Large Rifle) – For large-bore handgun cartridges using rifle primers.
- CCI 350 (Large Pistol Magnum) – Required for 44 Magnum loads.
In tactical or hunting scenarios, the CCI 450 is often the top choice for Accurate No. 11FS in the 300 Blackout due to its thick cup and consistent brisance. When loading magnum revolvers, the Federal 200 provides a slight edge in sensitive ignition, which can be beneficial if the firearm has a lightened trigger or hammer spring.
Conclusion & Expert Verdict
Accurate No. 11FS is a specialized tool that excels when used within its intended parameters. It is not a “universal” powder that should be used for light target loads in a 38 Special; rather, it is a high-performance propellant that requires pressure to “wake up” and burn efficiently. Its integrated flash suppression makes it one of the few powders on the market that explicitly considers the needs of the low-light shooter, and its metering characteristics are among the best in the industry.
For the 300 Blackout reloader, Accurate No. 11FS offers a compelling alternative to more traditional choices, providing a clean-burning, high-velocity solution that functions reliably in a variety of gas systems. In the realm of magnum handguns, it provides the consistency and power needed for long-range hunting and competitive silhouette shooting. While it requires careful attention to primer selection and charge weight precision, the results in terms of downrange performance and signature reduction are well worth the effort.
Expert Pro Tip: When working up loads for Accurate No. 11FS in the 300 Blackout, aim for a load that achieves at least 90-95 percent case fill. Spherical powders like Accurate No. 11FS exhibit their best standard deviation (SD) and extreme spread (ES) numbers when there is minimal “air space” in the case, which ensures that the primer’s flame front hits the powder column uniformly every time.
