Wednesday, April 9, 2014

75 Yard Chickens

A couple of weeks ago I went to the range to shoot my half scale chickens at 75 yards. They would be fun and also good for working on my benchrest form since the body was about the same size at the paper bull on the 75 yard target at Extreme Benchrest in Arizona. Each chicken weighs a two and a half pounds and their weight makes for a slow motion fall that connotes power. My rifle is a ,25 caliber Benjamin Marauder. And yes, it will down a half scale chicken at 75 yards.

It will only down all the chickens I can hit, and on this day I was bating 500. I shot about 40 pellets and only brought down just over 20. With a 24X scope I can spot all my hits and misses, but about half of my misses threw up dirt from behind the bird suggesting that those misses were passing just over the bird's back and doping out of sight before hitting the berm about 4 feet further on.

What to do?

To look for the suspected high shots on my next trip to the range, I took a half scale ram target. It is OK to shoot at chicken targets to test your marksmanship, but when you are testing a supposition, the target needs to be far larger to capture all the high or low shots. I could have taken paper but the sound of the pellets on steel is too good to pass up. I shot at 75 yards since my goal to shoot BR at that range, but also because, variability in velocity brought on by changes in pressure in the gun's air cylinder are more apparent at longer ranges.

Results - Some good some not so good.

I shot four, 24 shot sequences. Each time the starting pressure was between 3000 and 2900 psi and the ending pressure was between 2000 and 1900 psi. That's one clip more then I thought I was going to get when I bought the gun. Airgunners are always happy when their precharged gun has a longer then expected shot count.

But, there were high shots. More then I expected. The first, eight shot clip shot to the point of aim (POA), but the second clip went 1 ¼ inch high, and the third clip worked its way back down to the cross hairs. The 24th shot would go three inches low. This cycle repeated itself in each 24 shot string. A few shots went high or low, but the procession of hits stayed the same. On the fourth string I compensated by holding low on the second clip and shot a better. Those hits are in the middle of the shot pattern on the pig in the photo. The horizontal stringing on the pig and the ram are the effects of the wind. Beeman Kodiak Match pellets were used.

This time my Marauder showed the potential to put all shots into three inches at 75 yards. My goal is to shoot 25 shots into a two and a quarter inch circle at that range.