Buy H4350® Extreme Rifle® Powder – Hodgdon Powder Co.

Last reviewed: 2026-04-18 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.

Hodgdon H4350 powder is an extruded rifle propellant engineered for cartridges running medium to heavy bullets at magnum velocities. The H4350 formula uses shortened extruded grains that meter uniformly through progressive and single-stage powder measures, and the Extreme line’s temperature stability keeps velocity swings under 1 fps per degree Fahrenheit across a 160-degree range. Reloaders chamber it in .243 Winchester, 6mm Remington, .270 Winchester, .338 Winchester Magnum, and the full WSM family — .270 WSM, 7mm WSM, .300 WSM, .325 WSM — where it delivers consistent pressures from sub-zero prairie hunts to desert summer shooting.

Built for the Box

Hodgdon manufactures H4350 as an extruded stick powder with cylindrical grains approximately 0.045 inches long and 0.007 inches in diameter. The shorter grain length, introduced in the Extreme reformulation, flows through cavity measures with less bridging than older long-cut propellants, improving charge-to-charge consistency by 0.1 to 0.2 grains when metered volumetrically. The powder’s burn rate positions it between IMR 4350 and Hodgdon H1000 on the relative quickness scale — slower than the 4320 series, faster than the 4831 cuts — making it ideal for standard-length magnums and overbore 6mm and 6.5mm cartridges pushing 140- to 180-grain bullets. Chemical inhibitors in the Extreme formulation stabilize burn rate across ambient temperatures; the manufacturer’s testing shows velocity deviation of less than 30 fps between loads fired at -40°F and +125°F, compared to 80–100 fps swings with non-temperature-stable powders at identical charge weights.

Specs at a Glance

Reloaders match H4350 to .243 Winchester with 95–105-grain bullets, 6mm Remington with 100–115-grain projectiles, .270 Winchester across the 130–150-grain range, and the .338 Winchester Magnum with 180–225-grain hunting bullets. The powder also anchors loads in the Winchester Short Magnum family — .270 WSM, 7mm WSM, .300 WSM, .325 WSM — where its moderate bulk density fills 60–75% of case capacity at optimal charge weights, leaving sufficient air space for consistent ignition without compressed loads. For additional gun powder options across the burn-rate spectrum, explore our propellant inventory by cartridge application.

Who It’s For

H4350 suits precision rifle competitors running 6mm Creedmoor, 6.5 Creedmoor, and .260 Remington in mid-range competition, where the temperature stability holds zero across morning-to-afternoon relay strings without requiring velocity re-verification. Long-range hunters working magnums in variable climates — elk hunters running .300 WSM in September alpine weather, then verifying zero in January snow — see consistent point-of-impact holds when atmospheric temperature swings 60 degrees between load development and field deployment. The powder’s metering characteristics benefit progressive press operators loading .308 Winchester family cartridges in volume; the shortened grains cut bridging in Dillon, Hornady, and RCBS powder measures, reducing charge weight standard deviation to 0.15 grains or better when drops are calibrated and the hopper kept above half-full.

Storage & Handling

Store H4350 canisters in a cool, dry location away from heat sources, open flames, and direct sunlight. The DOT 1.4C hazmat classification permits ground shipment but requires specialized carriers for delivery — verify your jurisdiction’s storage quantity limits before ordering multiple 8# containers. Keep powder in its original labeled canister; transferring to unmarked containers introduces identification risk. Seal canisters tightly after each use to prevent moisture absorption, which degrades ignition consistency and accelerates chemical breakdown. Do not mix H4350 lots; each manufacturing run carries a unique lot number printed on the label, and burn rates can vary by 1–2% between lots. Cross-contamination with faster or slower powders creates unpredictable pressure spikes.