Shotgun shooting high calculation

[chesterse]

Just done an interesting experiment as there seemed to be something wrong with the fit of my shotgun.

Whilst clay shooting I have been consistently missing fairly close loopers and simple going away birds, especially if dropping.

I set up a paper pattern plate at 10 yards away shooting at small drawn in targets about the size of a two p coin. Shooting from about 5 ft high at the target 5 ft high.

I was using tight chokes, 3/4 and full making a small round hole 2" high of the target.

I am no mathematician but I calculated that at 30 yards I would be 18" above the target.

I know most of you will have fallen asleep by now but there must be some mathematical geeks out there who can tell me if I am right or wrong!

[Rewulf]

Just done an interesting experiment as there seemed to be something wrong with the fit of my shotgun.

Whilst clay shooting I have been consistently missing fairly close loopers and simple going away birds, especially if dropping.

I set up a paper pattern plate at 10 yards away shooting at small drawn in targets about the size of a two p coin. Shooting from about 5 ft high at the target 5 ft high.

I was using tight chokes, 3/4 and full making a small round hole 2" high of the target.

I am no mathematician but I calculated that at 30 yards I would be 18" above the target.

I know most of you will have fallen asleep by now but there must be some mathematical geeks out there who can tell me if I am right or wrong!

 

So if you line the pip up with the rib at 10 yards 2" above? Sounds about right.

Ask yourself this,if it was shot straight where you aimed it ,would you see the target (your barrels would obscure it ) what about the shot dropping off at 30 + yards ?

I always put the pip below the target.

Do some more pattern testing at different ranges to see exactly how high it shoots.

[chesterse]

Basically I was blotting the target out with the bead, but like you Rewulf when actually shooting I like to see the clay above the barrels.

 

Yes also I will also do the obvious and actually pattern it at 30 yards.

[oldypigeonpopper]

hello, i always thought you pull through a target eg clay unless coming straight at you then you aim on, law of speed V pattern/ choke

[wymberley]

You could start with the conventional approach and pattern at 16 yards. For every inch up/down/left/right away from where you wish the pattern to centre would (in theory) require a 1/16" adjustment of the comb and go from there.

[Rewulf]

hello, i always thought you pull through a target eg clay unless coming straight at you then you aim on, law of speed V pattern/ choke

 

You do ,but your point of aim still needs to be somewhere abouts

As said,its a lot more obvious when using a sporting gun on a DTL bird.

Sporters generally shoot high.

[motty]

 

So if you line the pip up with the rib at 10 yards 2" above? Sounds about right.

Ask yourself this,if it was shot straight where you aimed it ,would you see the target (your barrels would obscure it ) what about the shot dropping off at 30 + yards ?

I always put the pip below the target.

Do some more pattern testing at different ranges to see exactly how high it shoots.

Eh?

[TIGHTCHOKE]

Get out and see a coach to check gun fit and shoot some moving targets.

[moor man]

Eh?

LOL !!

[johnphilip]

You could start with the conventional approach and pattern at 16 yards. For every inch up/down/left/right away from where you wish the pattern to centre would (in theory) require a 1/16" adjustment of the comb and go from there.

This is how i was told to do it. Plus you say small hole in target.are you sure its not your Wad making the hole maybe .

[chesterse]

Get out and see a coach to check gun fit and shoot some moving targets.

It's a bit more complex than I let on.

It all started when I had the gun fitted by a competent gunsmith with an excellent reputation. He's made some alterations to the stock but unfortunately before I could try it I lost quite a bit of weight through illness.

Now I'm shooting again my scores dropped dramatically and especially as mentioned on closer targets like loopers and going away birds. So I have shot it , probably about 400 shells.

I had a dilemma, was my the loss of weight throwing out the gunfit or was the gunfit inherently wrong?

Before going back to the gunsmith I thought I would pattern it and to me it seems to be shooting high for a sporter.

I have another gun which I know shoots flatter so I will try that on Wednesday and will see what happens with that.

[Rewulf]

Eh?

 

Youre not one of these people who think shot or bullets travel in straight lines are you ?

[buze]

Wether the gun appears to shoot high, or low, depends on the gun and the amount of rib you see when shooting. Some guns inherently shoot 'low' (like, my side by side) and you need to put the clay 'on' the bead to break it... but some other do shoot 'high', especially for example if they have a higher comb. My Browning is like that (it's a trap gun) and I have to put quite a bit of 'air' between the bid and the clay to break it.

 

My problem with the pattern plate is that it's pretty easy to 'twitch' when shooting it, making the result next to useless. Shooting a moving target involves inertia and a bit of gyroscopic effect, so you shoot /steadier/ on moving targets than on slow ones --- and you shoot the 'worst' when shooting the pattern plate. That's why 'maintained lead' on far target is hard, while 'pull away' breaks them, you manufactured inertia to counter the fact the barrels are moving slowly.

 

I haven't found the pattern plate /terribly/ useful in 'sussing' a gun, it gives a rough idea, but ultimately there's nothing better than taking ONE target, like a nice crosser, and hammer at it until you break it consistently. Might take 10 shots. Might take 30. But the result will be your brain getting it's 'sight picture'. If 'sussing' a gun, don't doubt your 'lead', it's probably just fine: just work on the high/low picture.

 

Disclaimer: I'm just an engineer.

[Guest cookoff013]

It's important.

 

Q: where was the moon?

[bornfree]

Just done an interesting experiment as there seemed to be something wrong with the fit of my shotgun.

Whilst clay shooting I have been consistently missing fairly close loopers and simple going away birds, especially if dropping.

I set up a paper pattern plate at 10 yards away shooting at small drawn in targets about the size of a two p coin. Shooting from about 5 ft high at the target 5 ft high.

I was using tight chokes, 3/4 and full making a small round hole 2" high of the target.

I am no mathematician but I calculated that at 30 yards I would be 18" above the target.

I know most of you will have fallen asleep by now but there must be some mathematical geeks out there who can tell me if I am right or wrong!

That's about perfect. It allows you to keep the clay in view above the gun.

[Hamster]

 

Youre not one of these people who think shot or bullets travel in straight lines are you ?

 

You're not one of those people who thinks you need to adjust for drop at 30 yards ? Or any shotgun distance for that matter.

[wymberley]

Just done an interesting experiment as there seemed to be something wrong with the fit of my shotgun.

Whilst clay shooting I have been consistently missing fairly close loopers and simple going away birds, especially if dropping.

I set up a paper pattern plate at 10 yards away shooting at small drawn in targets about the size of a two p coin. Shooting from about 5 ft high at the target 5 ft high.

I was using tight chokes, 3/4 and full making a small round hole 2" high of the target.

I am no mathematician but I calculated that at 30 yards I would be 18" above the target.

I know most of you will have fallen asleep by now but there must be some mathematical geeks out there who can tell me if I am right or wrong!

 

 

That's about perfect. It allows you to keep the clay in view above the gun.

Just how big are these clays?

[bornfree]

30 yards. centre of an 30" pattern 18" above the target perfect.

[wymberley]

30 yards. centre of an 30" pattern 18" above the target perfect.

I'm afraid I don't see this. Even if you accept that the effective spread of a pattern is 30" which it is not - it's closer to 20" - then if the centre is 18" above the target you'll miss it by 3" but I would argue that in reality that figure would be c8". Unless it's because I'm getting old and tired,I simply can't follow your point of view. Sorry, I'm obviously missing something here.

[deershooter]

Just done an interesting experiment as there seemed to be something wrong with the fit of my shotgun.

Whilst clay shooting I have been consistently missing fairly close loopers and simple going away birds, especially if dropping.

I set up a paper pattern plate at 10 yards away shooting at small drawn in targets about the size of a two p coin. Shooting from about 5 ft high at the target 5 ft high.

I was using tight chokes, 3/4 and full making a small round hole 2" high of the target.

I am no mathematician but I calculated that at 30 yards I would be 18" above the target.

I know most of you will have fallen asleep by now but there must be some mathematical geeks out there who can tell me if I am right or wrong!

Come down the skeet range on Wednesday stop on peg 3 and find out where it's shooting

[chesterse]

Come down the skeet range on Wednesday stop on peg 3 and find out where it's shooting

Thanks for the offer Deerhunter but going with the old fogeys to Kibworth.

[Rewulf]

 

You're not one of those people who thinks you need to adjust for drop at 30 yards ? Or any shotgun distance for that matter.

 

First of all,I never said you had to adjust for drop at 30 yards.

But if you think that your shot hasnt dropped at 30 ,then you may be shocked to learn that any projectile starts dropping as soon as it leaves the barrel.

Sorry thats just physics.

What do you call any shotgun distance ?

Max 60 yards,or further ?

Pattern compensates for drop at sensible ranges,but if we are talking very heavy loads at extreme ranges ,100 yards + ,drop will need to be factored in.

 

Edit :Listen to what he says at 3.45

Edited November 15, 2016 by Rewulf

[neutron619]

I'm afraid I don't see this. Even if you accept that the effective spread of a pattern is 30" which it is not - it's closer to 20" - then if the centre is 18" above the target you'll miss it by 3" but I would argue that in reality that figure would be c8". Unless it's because I'm getting old and tired,I simply can't follow your point of view. Sorry, I'm obviously missing something here.

 

I suspect the figure the OP has forgotten to include is the pattern diameter at the original range of 10 yards. With an idealized full choke, this should be around 9".

 

To try to inject some sense into this discussion, a few simple points:

 

First, you need to understand that because we're dealing with a shotgun, the places where the pattern hits are different to the point of aim. The relationship between pattern impact point and point of aim is a linear calculation. Ignoring acceleration due to gravity for a moment, this means that if your pattern is hitting the place 2" higher than the point of aim at 10 yards, it will hit 2" higher still for every 10 yards after that. Therefore at 30 yards, assuming all other possible variables are eliminated, the center of the pattern should be 6" above the point of aim.

 

Second, to address the point of confusion others seem to have hit here. If your pattern is around 9" in diameter at 10 yards, and the center is impacting approximately 2" above the point of aim, then the top of the pattern at 30 yards will be in the region of 21"-24" above the point of aim. This is necessarily an approximation, reasoned from the fact that the center of the pattern will be 6" above the point of aim at 30 yards and that the 9" pattern at 10 yards will probably have expanded to somewhere around 33-36" in diameter at 30 yards (a nominal full choke should put nearly all of it's shot into a 30" circle @ 30yd). 6" plus 16.5"-18" is roughly 21"-24"

 

Third, pellet drop. The drop of shotgun pellets isn't significant at all useful ranges of a shotgun. I seem to remember (but don't have the tools to calculate it available at this point) that the drop of birdshot at 100 yards is between 2-4 feet, depending on shot size, initial velocity, shot type, etc. Even if that's wrong, I do remember that it's not significant enough to make any difference to one's shooting. At 30 yards, it's probably only a couple of inches, which in a 30"+ pattern diameter isn't significant in terms of bird shooting. If you're relying on the outer 2" of the pattern at the top, then any kills you make are what I'd call "lucky misses" rather than "hits".

 

Fourth, the pattern center itself. Theoretically, a shotgun pattern is normally distributed, but ultimately random. If you shot cartridges with literally thousands of pellets, you'd have enough hitting the paper / cardboard / plate to see this effect reasonably clearly - a dense center, with a smooth decrease in the gradient of pattern density as you move away from the center of the pattern. However, normal hunting cartridges don't have nealy enough pellets in them for this distribution to be clearly shown, except at very short ranges.

 

Ignoring acceleration due to gravity, think of the pattern as though it was a clock face. The point of aim is the middle of the clock face and this should be where the center of the pattern hits. In fact, assuming you shoot straight, it always is. However, because of the random nature of the pellet distribution, it might just happen that more pellets end up in the shape drawn between the central point, 4 'o clock and 5 'o clock. When you actually go to draw the circle and try to center it around the main area of pellet impacts, you find that the center of that circle doesn't line up with the center of the clock face.

 

What's going on? Nothing particularly strange. You just happen to have thrown more pellets into one segment of the clock face than the others, which makes it look like the pattern isn't centered on the point of aim. Unfortunately, this is just something that happens from time to time and it is unwise to draw conclusions about gun fit without repeating the test several times in a number of different ways. As with all probability functions, the Normal distribution tells you where the pellets are likely to end up, expressed as an average of an infinite number of tests. It cannot predict the outcome of a specific test case.

 

It is perfectly possible, albeit, extremely improbable, that the next time you fire your cartridge at the pattern plate, that the pellets will group together in such a way as to spell your name. Extraordinarily unlikely, but within the realms of possibility.

Edited November 15, 2016 by neutron619

[wymberley]

 

I suspect the figure the OP has forgotten to include is the pattern diameter at the original range of 10 yards. With an idealized full choke, this should be around 9".

 

To try to inject some sense into this discussion, a few simple points:

 

First, you need to understand that because we're dealing with a shotgun, the places where the pattern hits are different to the point of aim. The relationship between pattern impact point and point of aim is a linear calculation. Ignoring acceleration due to gravity for a moment, this means that if your pattern is hitting the place 2" higher than the point of aim at 10 yards, it will hit 2" higher still for every 10 yards after that. Therefore at 30 yards, assuming all other possible variables are eliminated, the center of the pattern should be 6" above the point of aim.

 

Second, to address the point of confusion others seem to have hit here. If your pattern is around 9" in diameter at 10 yards, and the center is impacting approximately 2" above the point of aim, then the top of the pattern at 30 yards will be in the region of 21"-24" above the point of aim. This is necessarily an approximation, reasoned from the fact that the center of the pattern will be 6" above the point of aim at 30 yards and that the 9" pattern at 10 yards will probably have expanded to somewhere around 33-36" in diameter at 30 yards (a nominal full choke should put nearly all of it's shot into a 30" circle @ 30yd). 6" plus 16.5"-18" is roughly 21"-24" 21:9, 70:30, where have I heard that before?

 

Third, pellet drop. The drop of shotgun pellets isn't significant at all useful ranges of a shotgun. I seem to remember (but don't have the tools to calculate it available at this point) that the drop of birdshot at 100 yards is between 2-4 feet, depending on shot size, initial velocity, shot type, etc. Even if that's wrong, I do remember that it's not significant enough to make any difference to one's shooting. At 30 yards, it's probably only a couple of inches, which in a 30"+ pattern diameter isn't significant in terms of bird shooting. If you're relying on the outer 2" of the pattern at the top, then any kills you make are what I'd call "lucky misses" rather than "hits".

 

Fourth, the pattern center itself. Theoretically, a shotgun pattern is normally distributed, but ultimately random. If you shot cartridges with literally thousands of pellets, you'd have enough hitting the paper / cardboard / plate to see this effect reasonably clearly - a dense center, with a smooth decrease in the gradient of pattern density as you move away from the center of the pattern. However, normal hunting cartridges don't have nealy enough pellets in them for this distribution to be clearly shown, except at very short ranges.

 

Ignoring acceleration due to gravity, think of the pattern as though it was a clock face. The point of aim is the middle of the clock face and this should be where the center of the pattern hits. In fact, assuming you shoot straight, it always is. However, because of the random nature of the pellet distribution, it might just happen that more pellets end up in the shape drawn between the central point, 4 'o clock and 5 'o clock. When you actually go to draw the circle and try to center it around the main area of pellet impacts, you find that the center of that circle doesn't line up with the center of the clock face.

 

What's going on? Nothing particularly strange. You just happen to have thrown more pellets into one segment of the clock face than the others, which makes it look like the pattern isn't centered on the point of aim. Unfortunately, this is just something that happens from time to time and it is unwise to draw conclusions about gun fit without repeating the test several times in a number of different ways. As with all probability functions, the Normal distribution tells you where the pellets are likely to end up, expressed as an average of an infinite number of tests. It cannot predict the outcome of a specific test case.

 

It is perfectly possible, albeit, extremely improbable, that the next time you fire your cartridge at the pattern plate, that the pellets will group together in such a way as to spell your name. Extraordinarily unlikely, but within the realms of possibility.

From the use of "targets (plural) I think the OP is aware that he needs to take an average assessment.

[Hamster]

 

First of all,I never said you had to adjust for drop at 30 yards.

But if you think that your shot hasnt dropped at 30 ,then you may be shocked to learn that any projectile starts dropping as soon as it leaves the barrel.

Sorry thats just physics.

What do you call any shotgun distance ?

Max 60 yards,or further ?

Pattern compensates for drop at sensible ranges,but if we are talking very heavy loads at extreme ranges ,100 yards + ,drop will need to be factored in.

 

Edit :Listen to what he says at 3.45

 

Ordinary shotgun range 15-65 yards nobody takes shot drop into the equation, scatter guns just don't work like that.