.375 Fl. Mag. N.E. Load Data & Reloading Guide
Also known as: .375 Flanged Magnum Nitro Express, .375 Nitro Express, .375 NE, .375 Fl. Mag.
About .375 Fl. Mag. N.E.
The .375 Flanged Magnum Nitro Express, often referred to as .375 Fl. Mag. N.E., originated in the early 20th century as a rimmed variant of the .375 H&H Magnum. Designed for use in double rifles, it aimed to provide a powerful and reliable option for hunters pursuing dangerous game. Its development was primarily influenced by the need for a cartridge that combined the ballistic efficiency of the .375 H&H with the dependability required for use in break-action firearms.
Technically, the .375 Fl. Mag. N.E. features a robust rimmed case suitable for strong extraction in double rifles and single-shot rifles. It shares the same bullet diameter and overall ballistics as the .375 H&H, including similar pressures. This cartridge utilizes a case length of 2.85 inches and typically operates at a pressure around 47,000 psi, which is slightly lower than that of its belted counterpart to accommodate older firearm designs.
In terms of ballistic performance, the .375 Flanged Magnum N.E. is well-regarded for its versatility and stopping power. Typical bullet weights range from 270 to 300 grains, providing a balanced trajectory and considerable energy delivery. It remains a preferred choice for hunting large and dangerous game, such as Cape buffalo and African lion, especially in situations where reliability and a quick follow-up shot are essential.
For reloaders, the .375 Fl. Mag. N.E. presents several advantages. Its rimmed design simplifies headspacing and ensures smooth cycling in break-action rifles. While factory ammunition can be scarce, reloaders have the opportunity to tailor loads to their specific needs, optimizing bullet choice and powder selection for different hunting conditions. The availability of high-quality brass cases manufactured by companies that specialize in classic calibers further supports the customizability and longevity of reloaded ammunition in this caliber.
Technical Drawing

Technical Specifications
Start Calculating to Develop your own Load Data for .375 Fl. Mag. N.E.
Use our professional ballistics calculator to develop safe and accurate load recipes for .375 Fl. Mag. N.E..
Start CalculatingStandard Load Data — .375 Fl. Mag. N.E.
Select your desired cartridge and bullet weight below to access the corresponding load table. From there, you can choose any listed load recipe and transfer it directly into the ballistics calculator for further refinement, optimization, and precision tuning.
.375 | 350gr | MAKER REX SUB
.375 | 255gr | Winchester Soft-Point
.375 | 200gr | MAKER TREX
.375 | 185gr | Lehigh Defense Controlled Fracturing
.375 | 250gr | Lehigh Defense Controlled Fracturing
.375 | 270gr | Lehigh Defense Controlled Fracturing
.375 | 270gr | Barnes LRX BT
.375 | 175gr | Lehigh Defense Match Solid
.375 | 175gr | Lehigh Defense Controlled Fracturing
.375 | 260gr | Nosler Ballistic Tip
.375 | 260gr | Nosler AccuBond
.375 | 270gr | Nosler CT FailSafe
.375 | 250gr | Speer TBBC
.376 | 270gr | Peregrine VRG-3
.376 | 277gr | Peregrine VRG-2
.375 | 260gr | Nosler Solid
.375 | 270gr | Woodleigh RN SN
.376 | 300gr | Peregrine VRG-3
.376 | 307gr | Peregrine VRG-2
.375 | 250gr | Alaska Bullet Works Kodiak SP SPBC
.375 | 300gr | Nosler Partition
.375 | 300gr | Nosler AccuBond
.375 | 300gr | Nosler CT FailSafe
.375 | 270gr | Alaska Bullet Works Kodiak PP SPBC
Frequently Asked Questions
The maximum pressure for .375 Fl. Mag. N.E. is 47,137 psi | 3,250 bar.
.375 Fl. Mag. N.E. typically uses a Large Rifle Magnum (LRM) primer.
The case capacity of .375 Fl. Mag. N.E. is approximately 94.1 grains of water (H₂O).