Abnormal discharge of shotgun

Stevefancypix said:
My frame rate on the camera was 60 fps. If you don't know, means 60 individual images per second. Gopro has capability of shooting at 120 fps.

I just did a thorough cleaning of my choke tubes and they were pretty grimy. If I have to guess i'm thinking that's the cause. @denydart Your suggestion of trying to recreate it at 5 yards or so is a good idea. I'll definitely try that and hopefully the deep clean on the chokes solves the problem. @Canuck65 It does not seem like there is a ridge between the bore or the chokes and the bores seem spotless. It makes me think the major cause would be significant carbon build up on the chokes themselves being that is a constriction point with the build up of psi as you were mentioning. Thoughts?
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Right, I was thinking of shutterspeed, which I see online is something Go-Pro's can have adjusted with 1/2000th of a second being the fastest (depending on model anyway). For argument's sake, if muzzle velocity should have been 1200fps then the pellets should be super blurry from travelling 8" during that opening of the shutter, right? If they were going considerably slower than that, what the pictures show makes more sense. Are those two pictures different frames from the same shell's discharge? The birds look like they're the same. Did those loads sound and recoil like you'd expect or did muzzle blasts seem abnormal? Have you recorded other loads and did they display the same way in camera footage?

I'm really interested to see what patterning on paper shows you. I still can't understand how any combination of choke type, damaged choke or muzzle imperfection and wad / torn wad / no wad could make shot spread in what looks like a 90 degree pattern. Some of the angles of the dark streaks in the blurrier picture don't even look like they started at the muzzle either.
 
denydart said:


Right, I was thinking of shutterspeed, which I see online is something Go-Pro's can have adjusted with 1/2000th of a second being the fastest (depending on model anyway). For argument's sake, if muzzle velocity should have been 1200fps then the pellets should be super blurry from travelling 8" during that opening of the shutter, right? If they were going considerably slower than that, what the pictures show makes more sense. Are those two pictures different frames from the same shell's discharge? The birds look like they're the same. Did those loads sound and recoil like you'd expect or did muzzle blasts seem abnormal? Have you recorded other loads and did they display the same way in camera footage?

I'm really interested to see what patterning on paper shows you. I still can't understand how any combination of choke type, damaged choke or muzzle imperfection and wad / torn wad / no wad could make shot spread in what looks like a 90 degree pattern. Some of the angles of the dark streaks in the blurrier picture don't even look like they started at the muzzle either.
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You are onto something in regards to the speed of the shot and the shutter speed. It might be difficult to know what the settings were as GoPro would automatically be adjusting shutter speed in video mode to compensate for light exposure changes. The two images shown are sequential frames from the same discharge. The bottom images first and top images second. I don't recall the sound or recoil feeling any different, but when birds come up I tend not to notice either. I'll record video at a faster frame rate when I pattern the gun to document the blasts to compare the different shells.

You query about the shot spread of 90 degree from the muzzle is the same as I have. Doesn't make much sense to me.
 
Paper patterns at 10 and 20 yds will confirm suspicions. I think the blurred spots you believe are wayward pellets are unburned powder granules but a pattern on paper will tell all. Friends who have chronnied shotshell handloads have had problems with powder grains messing up measurement of actual shot load velocities.
 
Ol' Flinter said:
Paper patterns at 10 and 20 yds will confirm suspicions. I think the blurred spots you believe are wayward pellets are unburned powder granules but a pattern on paper will tell all. Friends who have chronnied shotshell handloads have had problems with powder grains messing up measurement of actual shot load velocities.
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Do you have any experience with shotguns or patterning?? Haha see you tomorrow most likely!!
 
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