Pellet flight path

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bubblerboy64

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Jul 25, 2018
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Pa, United States
I’d like to question the knowledgeable among us concerning flight path of pellets from a PCP. 

I have noticed that as I advance in range my windage seems to shift. Now I’m talking about ideal conditions . It would seem to me that when sighted dead on at 50 yards advancing to 75 or 100 should only result in a vertical drop . I’m finding that windage is changing as well and by significant amounts. 

My only explanation is that the pellets are spiraling in flight Spin drift ? 

Your thoughts? John Heckman 
 
Seems it could be spiraling, wind, or alignment/cant. Alignment/cant issues should be eliminated with proper setup and using a level. Spiraling should be identifiable through shooting. Wind seems to be the most unpredictable and least easily identifiable factor (especially when it is light but variable) and seems likely to be the most common basis for such results.
 
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I’m not the greatest shot but I’ve done a bunch of it and I understand rifle cant and scope alignment and also parallax errors AND WIND. Or at least I think I do. I’m not suggesting that any of these factors might be part of this but this PCP ( right now I’m shooting an impact MK ll 25 cal ) It just seems I’m experiencing way more windage shift then I can account for. NOW it could be that it’s just the fact that shooting air rifles at distances beyond 75 yards is equivalent to powder burners at 4 or 5 hundred . Maybe I’m just not familiar enough to know what to expect.

Bob as far as groups at 100 yards. I’m testing slugs and I haven’t been able to get much better then about 1 1/2 at best. It’s driving me nuts because I can get 3 or 4 hitting around 1/2 inch but I almost always have one out of the group opening it up to at least twice that.

It’s difficult to isolate one variable but it goes like this. I’ll shoot at 100 and get things hitting reasonably well and then come back to let’s say 75 yards (which is about where I like to be for pest birds) and I’ll expect my vertical to need adjustment but the windage will be off several inches and I can’t account for that much considering the other factors we have discussed. Same way with pesting One spot is 45 to 50 and another spot is 67 . There is of course a considerable change in vertical but the last time I moved farm to farm the windage was off as far as the vertical and I just could not account for that .

Seems like I’m throwing curve balls. 

Sorry to go on so long just trying to be as clear as possible with my question. I can pretty consistently knock off a sparrow at 50 yards AFTER I get sighted in . But my POI just seems to be off right and left more then what I can account for.

Just wondering if others experience this and seems that some do.

I do a fair amount of GH hunting and if the wind is calm my shots are pretty consistently on out to 3 or 4 hundred yards as long as I have the drop figured correctly. I’ll shoot over them at times but I don’t find unaccounted for windage variations like I do with the air guns. 

And I know you can’t help me much over the web. Just wondering what and if others are experiencing this. 

It would be interesting to be able to film in slow motion the flight of the pellet as it travels. Only way I’d know to test my theory (or concern) 
 
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I think wind is a factor that people frequently underestimate, or overestimate ability to judge it accurately. With my firearms, I have several rifles that shoot sub-MOA at 100 but on anything but a perfectly calm day groups at 500 can open to over a foot (and more) very easily. My view is that pellets would probably perform similarly once beyond maybe 60 to 75 yards due to their rapid loss of velocity but I rarely shoot air guns at those ranges. Since you believe you have a handle on other factors, I would suggest shooting closer initially (maybe 40-50 yards) and gradually move out while looking for a pattern. All in a narrow time window on a still day of course.
 
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I think wind is a factor that people frequently underestimate, or overestimate ability to judge it accurately. With my firearms, I have several rifles that shoot sub-MOA at 100 but on anything but a perfectly calm day groups at 500 can open to over a foot (and more) very easily. My view is that pellets would probably perform similarly once beyond maybe 60 to 75 yards due to their rapid loss of velocity but I rarely shoot air guns at those ranges. Since you believe you have a handle on other factors, I would suggest shooting closer initially (maybe 40-50 yards) and gradually move out while looking for a pattern. All in a narrow time window on a still day of course.
Click to expand...

What I am going to try at some point is shooting at 100 indoors. There is a range available within driving distance . That should answer a lot of my questions . OR will it? Hopefully.
 
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I think wind is a factor that people frequently underestimate, or overestimate ability to judge it accurately. With my firearms, I have several rifles that shoot sub-MOA at 100 but on anything but a perfectly calm day groups at 500 can open to over a foot (and more) very easily. My view is that pellets would probably perform similarly once beyond maybe 60 to 75 yards due to their rapid loss of velocity but I rarely shoot air guns at those ranges. Since you believe you have a handle on other factors, I would suggest shooting closer initially (maybe 40-50 yards) and gradually move out while looking for a pattern. All in a narrow time window on a still day of course.
Click to expand...

What I am going to try at some point is shooting at 100 indoors. There is a range available within driving distance . That should answer a lot of my questions . OR will it? Hopefully.
Click to expand...

Seems it would eliminate any wind effect and that should help a lot. I still think starting around 50 yards and moving out 5 or 10 yards at a time on a still day might tell you a lot about what is happening with your specific situation but indoors does have advantages.
 
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I wonder if your scope went bad.
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No Bob I have no evidence that it's the scope. In fact I would rank that after all the other variables mentioned. It's possible it's wind or even parallax error or cant or a combination of all.. I've learned from experience to NEVER say never but I'm shooting under conditions which are darned hard to beat. I have a range in my back yard and I don't shoot groups at 100 if I can detect any air. Or if I do I'll not be expecting one holers.

I've just been noticing this windage thing for a while with the air guns and I just haven't been able to convince myself that it's the things that have been mentioned. It very will may be. Maybe I just need to convince myself. You know admit my errors. 

I just threw this out there to see if other's are experiencing the same. I just seem to be chasing my zero's left and right a lot more then I think I should be. Lets let it at that for now. 

If I can do some 100 yard indoor shooting it should be a help. If I shoot at 50 and 75 and 100 indoors and am careful to eliminate the OTHER variables it should tell me what I need to know.

Lots to learn and a short time left to do it😁
 
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Something weird going on because slugs just don't drift that much in light winds...

Do you have a bubble level on your rig and are you sure your scope is perfectly level!

Doesn't Take much cant to throw things for a loop....

James from Michigan
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See I'm just not finding an advantage to slugs at 100. Yep when you get out beyond 100 I can see a distinct advantage, Now I am shooting 34 gr pellets out of the 25 cal impact and 44's out of the 30 RAW.

I don't have a level on the rig which I can get but my targets are such that I can detect cant by aligning the cross hairs on the scope to the lines on the target. I'm not just shooting at dots. If you mean by saying "scope level " having the vertical cross hair of the reticle plum? it is.
 
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If the scope is not optical centering you will get cross over. If you zero at 50 yards and half to adjust scope windage left or right off optical center you will only be zeroed at 50. 

Depending on how many clicks you had to adjust windage will determine how far off nearer and farther you will be. You could be far left at 20 yards dead on at 50 yards and far right at 80 yards, cross over.

The only way to correct this is with windage adjustable mounts, make sure the scope is optical centered and adjust the mounts to zero, no more cross over.
 
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I have noticed this happen. Where it’s dead on at say. 15 yrs then 30 I’m still good. Go to 50yd and holy cow I’m now over 5 in left or right and calm days. 
Observation #1 I have only noticed this with a .22 cal, .177 .30 and .25 don’t do it for me.

#2 not the gun bec both do it taipan and brocock grain of slug seems do worse with light ones. 
#3 using my side shot I recorded my pellet flight and it appears that running .22 at lower velocities it will just corkscrew most comparable to shooting paintball gun when it’s nearing its end of steam the balls kinda fly random.

#4 it’s stay under 40yds, use heavy pellets or crank the speed up to around 850-900 weight seems irrelevant just seems to enjoy the speed.

#5 spitballing but maybe length vs with to me .22 seems to act like bbs our a smooth bore at a certain velocity.
 
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You say it appears that the pellet is shooting a curve ball? I saw a video on YouTube, I think by Ted's Holdover, where you could see his pellets spiralling. It was with an Impact as well. Not every shot did it and I think he said he changed his tune to correct it. If you are wanting to see your pellets in action, use high scope magnification and a big black backdrop with small white target dots. It works pretty well.

Also, it may seem excessive to avoid a cant error, but here's what I did to square up my Impact because the scope sits so high above the barrel and to check my scope's tracking: 

Mount the gun in a vice so it is perfectly level and square with the universe. Hang a plumb string ten or more yards directly in front of the gun sight line. Attach and torque the scope mounts on the rail. Now, with the scope fairly loose in the mount's, rotate the scope until the cross hairs are perfectly vertical with the plumb string and then torque down the scope. 

Now that the barrel, scope, and cross hairs are perfectly plumb to the world, test the scope's tracking by moving the scope adjustments and shooting in a square pattern. I also go a bit further with these tests by checking if it tracks perfectly vertical all the way up and down it's adjustment range. You can either shoot this pattern, which is the norm, or simply look at how and where the cross hairs are tracking on a marked backdrop. 
 
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