My range time has been limited for the past year. In order to practice some wind reading, I have been shooting a 177 caliber Marauder PCP air rifle in the back yard at 50 yards. This has a Huma regulator set at 125 bar (about 1800 psi). I wanted to find how many shots I could get without coming off the regulator and keep the extremes spread as small as possible.
Air Arms 8.44 grain pellets had shot well at 25 yards, but at 50 yards they didn’t seem very accurate. Wind flags didn’t show much change when the pellets wandered around. For the 50 yard target, I decided to try ZAN 10 grain slugs and ZAN 13 grain slugs. I thought they might behave more like bullets than the pellets would. The 10 grain slugs seemed slightly more accurate than the 13 grain slugs.
I set up the Labradar to record velocities at muzzle (V0) 10 yards, 20 yards, 30 yards, 40 yards and 50 yards. I found that velocity stayed pretty close for 50 shots and regulated pressure stayed at 125 bar.
The pellets hit the paper and looked like they were key holing. Out of curiosity, I decided to run the extreme spread on the shot strings and also the standard deviation. Most often we just see muzzle velocities recorded. Since the chronograph was reading to 50 yards, I ran the Extreme Spread and Standard Deviation at each 10 yard interval.
The 10 grain slugs had the lowest extreme spread and lowest standard deviation at 50 yards. The pellets started getting wobbly at 30 yards. The 13 grain slugs had about twice the extreme spread as the 10 grain slugs. The pellets had a spread of 7.74 at 30 yards which was equal to the extreme spread of the 10 grain slugs at 50 yards.
