Problem fixed: 115 yard attempt and miss(with short video)

[Dave]

So I attempted a 115 yard shot with the Bobcat and missed by overshooting my target, so I decided to chrono gun again. I chronographed this gun when I first got it and averaged 877 fps and was using this data for the shot. Here is the video of the miss.

I now have about a tin of pellets through it, so it goes to show how things will change a little as it breaks in.
This time I moved the chronograph to 11" from muzzle to the first sensor. I then shot 3 full magazines and here is the data.
shots 1-9 shots 10-18 shots 19-27
883* 888* 892
893 893 894
890 894 896
891 890 897
894 895 895
891 896 894
896 895 895
895 896 897
893 896 896

Hi 897 LO 883 AVG 893 ES 14 SD 3

With the two * shots removed here is the final data

Hi 897 LO 890 AVG 894 ES 7 SD 2

This change effected POA enough that I was aimed too high. so changes have bee made and hope to not miss next time. Just thought I would share. Gear is as follows:
Pellets - JSB 44.75 grain
Chronograph - Competition electronics pro chrono with IR indoor lighting kit
Gun- FX Bobcat mk2 .30 cal

 

[Cal]

Noticed something here that I wonder if anyone else has experienced. The low velocity shots are both the first out of a new mag. I have a marauder pistol that is often extra fussy with the first pellet out of a fresh mag regardless of where I am in the fill string.. It can be pushed, pulled or fall a little low. After that it starts stacking again. Not way off, but noticeable. Curious.

 

[Dave]

"Cal"Noticed something here that I wonder if anyone else has experienced. The low velocity shots are both the first out of a new mag. I have a marauder pistol that is often extra fussy with the first pellet out of a fresh mag regardless of where I am in the fill string.. It can be pushed, pulled or fall a little low. After that it starts stacking again. Not way off, but noticeable. Curious.

The very first shot I took I hand loaded into gun instead of topping off magazine, since the first shot from mag was the missed shot. I also started at about 240-245 bar. This is my first regulated gun so hopefully someone with more experience will chime in.

kris- I am not sure if that is possible with chairgun, but I think you might be able to you a program like Microsoft excel in conjunction with chairgun. You would have to sight in with one at know distance and see the zero changes as you change velocities and then input your trajectory data manually into Excel for each. then you should be able to overlay them. Hopefully someone can provide a better way. 

 

[Dave]

Although chairgun shows a yard difference per the same aimpoint for the velocity change for this shot, I found the problem. When using the orion steadypix mount on this gun due to rail and mount clearance it pushes up on the back of scope slightly and changes the zero as you tighten it. It would be like using the FX no-limit mounts to change zero. I removed the mount and made sure zero back to normal and just took a 87 yard shot on a groundhog. He took it right in the thinker and instant lights out. The only movement was about a foot forward as he fell down the slight slope he was standing on.

My eagle vision mount will be here Tuesday so I will wait to do my pest control for a friend till I can use it. He owns a local Driving range and his mower and ball picker are getting damaged due to the holes the groundhogs leave in the middle of the range. Should be fun and interesting.