IMR 4831 Smokeless Powder

IMR 4831 has a slightly slower burn rate compared to IMR 4350. It delivers top velocities and exceptional performance with heavier bullets in medium-sized magnums, making it a versatile choice for many shooters.

Historical Significance

The legendary .270 WCF load, developed by Jack O’Connor using 20mm Oerlikon H4831 powder from World War II, remains an iconic example of ballistic innovation. While H4831 is no longer sold in paper bags for pennies per pound, its modern equivalent is almost indistinguishable in performance.

Applications by Cartridge

• .270 WCF:
  Many .270s perform well with 140-grain bullets. Based on personal experience, IMR 4350 tends to excel with 130-grain projectiles. However, IMR 4831 is a fantastic option, especially when loading 57-58 grains behind 130-grain Sierras. If a .270 rifle can’t handle this load, it might be unreliable.
• .30-06 Springfield:
  A lightweight Sauer .30-06 paired with 168-grain TSX bullets can achieve outstanding results. Another great load is 72 grains of powder paired with 225-grain flat-base TSX bullets for a Sako .338 Win Mag.
• 6mm Remington, .243 Win, 7mm Rem Mag, and Others:
  IMR 4831 shines across a broad range of calibers, delivering consistent accuracy and reliability.
• 300 Winchester Magnum:
  A popular load includes 71.0 grains of IMR 4831 under a 190-grain Sierra MatchKing (SMK) bullet, seated .005 off the lands. In a Savage 112 HB, this setup produces superb precision and one-hole groups at approximately 2800 fps.

Revolutionary Advancements

IMR 4831’s modern formula burns faster than the standard H4831, making it ideal for shooters seeking better efficiency without sacrificing performance.

Reliability and Performance

The versatility of IMR 4831 ensures it remains a go-to choice for many cartridges. Shooters consistently report reliable results across various platforms. For instance:

• Accubond 280 wt bullets with only 56 grains of powder deliver impressive performance.
• Some 270 WCFs achieve extraordinary accuracy using IMR 4831.

If a load like this doesn’t perform well, it may indicate issues with the firearm itself rather than the powder.