The Impact of Moisture on Rifle Accuracy:

An Experiment Introduction:

Maintaining consistent accuracy is a critical concern for both competitive shooters and hunters. The impact of moisture on ammunition performance is a topic that has long been debated, with many anecdotal reports but little in-depth testing. In this blog post, we'll dive into an experiment that explores how moisture affects pressure, velocity, and ultimately the point of impact when shooting at long range.

The Experiment Setup:

I set up at a 300-yard range, with a chronograph and 20 rounds of ammunition ready to test. The plan is to shoot a control group of dry rounds, then gradually introduce different levels of moisture to see how it affects the results.

Control Group:

The first five rounds are shot dry, establishing a baseline. The results show an average velocity of 2873 fps, with a standard deviation of 5.6 and an extreme spread of 14.9 fps - all within an acceptable range.

Lightly Misted Rounds:

Next, the narrator lightly mists the ammunition, simulating a light fog or drizzle. The bolt lift noticeably increases, and the group size opens up slightly. The average velocity increases to 2882 fps, with a higher standard deviation of 7.5 and extreme spread of 19.8 fps.

Heavily Wet Rounds:

The final test involves heavily wetting the ammunition, to the point where the rounds are dripping. The bolt lift becomes extremely difficult, and there are clear signs of increased pressure, with visible ejector marks on the cases. The group size increases further, and the point of impact shifts significantly compared to the dry control group - up to 1.5 inches at 300 yards.

The Importance of Keeping Ammunition Dry:

The experiment clearly demonstrates the importance of keeping ammunition dry, especially in competitive shooting or critical hunting situations. Even a small amount of moisture can affect velocity, pressure, and point of impact, potentially leading to errant shots or significant scoring changes. Conclusion: This detailed test provides valuable insights for shooters who need to maintain consistent accuracy, regardless of weather conditions. The results reinforce the importance of taking measures to protect ammunition from moisture, such as using a towel, rain cover, or other methods to keep the gun and ammunition as dry as possible. By understanding the real-world impact of moisture, shooters can better prepare for and adapt to challenging environmental conditions.