Powder Lot Variations: A Case Study with Varget - Hodgdon Extreme

TL;DR

This study investigates the velocity variations across different lots of Hodgdon Extreme Varget powder in two rifle loads, finding that lot-to-lot differences are consistent with manufacturer claims and are relatively small.

Contribution

The paper provides empirical data on lot-to-lot velocity variations of Varget powder, confirming that variations align with Hodgdon's claims and are smaller than those observed in other powders.

Findings

Velocity variations ranged from 7.9 to 45.6 ft/s across lots.

Velocity differences are moderately correlated between loads (r=0.54).

Lot-to-lot variations are smaller than those for other powders like H4831.

Abstract

Small arms propellant distributor Hodgdon claims that rifle powders in its Extreme line have small velocity variations with both temperature changes and lot number. This paper reports on the variations in average velocity of four different lots of Hodgdon Extreme Varget tested in two .223 Remington loads. Compared to the lot with the slowest average velocity, the other three lots of powder had higher average velocities ranging from 23.4 ft/s faster up to 45.6 ft/s faster with a 69 grain Nosler Custom Competition bullet and from 7.9 ft/s faster to 15.3 ft/s with the 53 grain Hornady VMAX. The mean velocity differences between lots are slightly correlated between the two loads with a correlation coefficient of 0.54. This correlation suggests that factors other than lot to lot variations contribute significantly to the measured velocity variations. Unlike the much larger lot to lot variations that were reported previously for H4831, lot to lot variations in velocity for Varget seem consistent with Hodgdon's marketing claims.