MOA Question

[benzy2]

Whatever the phenomenon referred to as "going to sleep" is, it is fact.

What exactly makes this fact outside of a few shooters thinking they notice such a phenomenon? I could say since my groups exponentially grow as distance increases that bullets not only travel out in a funnel, they intentionally try to miss what I'm aiming at. Does that make my statement any more fact than yours? Its what happens when I shoot. Must be fact. Right? Its a theory and that's all. Until there is hard data beyond a bunch of guys shooting in the wind it will be nothing more than a theory.

As for what is happening, well, there are a thousand variables to pick from. I would start by removing them one at a time if you really want to get to the bottom of what is happening.

 

[Zak Smith]

We recently had another thread about this that covered it in some detail.

However, I was one of the ones that posted I've never shot a rifle/load that would consistently shoot better at any further distance vs. closer. I have had quite a few loads that shot disproportionately worse at distance, and some that just plain acted funny at all distances.

-z

 

[M1key]

Right. It's just a theory.

Apparently you have never seen it, so you would never be compelled to try and explain it.

I do like cool videos, though. http://www.youtube.com/watch?v=KH9SCbCBHaY

 

[jon8777]

Thats a good video.

I have 5 on record groups with this load at 200 that range from .830 to .733".

I cant not find my 100 yard targets but they range in that .5-.8" range.


If the "going to sleep" groups were hapening to you, would you change something in your load?

 

[MCMXI]

Right. It's just a theory. Apparently you have never seen it, so you would never be compelled to try and explain it. I do like cool videos, though. http://www.youtube.com/watch?v=KH9SCbCBHaY

First off, that video merely shows the output from a computer MODEL, and furthermore, as it stands it's meaningless. Mr. Litz is a talented individual but the video is still meaningless and he should know better. However, if you want to use that video to convince yourself that the "going to sleep" theory is FACT then you're obviously free to do so.

The thing with the "going to sleep" theory is that it's a LAZY rationalization of what might be happening. It's convenient to explain it all away with such a catchy phrase and a neat little video but there are numerous complicated internal and external variables that could account for a reduction in MOA group size as a function of distance.

X MOA could be thought of as a circular area with diameter = X MOA in which the bullets are landing. If you shoot 1 MOA groups at 100 yards, your bullets are landing in an area of 0.861 in^2. However, the area of a 1 MOA circle at 200 yards is 3.45 in^2 and at 300 yards the area is 7.75 in^2. So the area is a function of the square of the group diameter (nothing new here). In other words, if you shoot 1 MOA groups at 300 yards (3 times the distance), your bullets are landing in an area 9 times that of the area enclosed by a 1 MOA circle at 100 yards!

If you wanted to only double the area of the group at 200 yards and triple it at 300 yards compared to the 1 MOA area at 100 yards, you'd need to shoot 1.481" (0.707 MOA) and 1.814" (0.577 MOA) groups at 200 and 300 yards respectively.

The OP mentioned 0.552" groups at 100 yards and 0.733" groups at 200 yards. The area of a 0.552" circle is 0.239 in^2 and the area of a 0.733" circle is 0.422 in^2. So double the distance and almost double the area of the group. Seems reasonable to me ... just as reasonable as the "going to sleep" theory.

Just a thought!

 

[Zak Smith]

The video does not show the path is inconsistent, just that is not exactly straight. IE, if the bullet path per the path graph is the same every time it would not support better accuracy at longer ranges.

 

[JDGray]

Great shooting!

I had that Bushnell Elite 3200 10x40 scope, and it had slight parallax at 100yrds, terrible at 200yrds, never did find it parallax free. You've got one fine shooting .223, and if your scope is anything like mine, you must have a very consistant shooting technique to shoot past the parallax error

 

[hadmanysons]

Right. It's just a theory.

Apparently you have never seen it, so you would never be compelled to try and explain it.

I do like cool videos, though. http://www.youtube.com/watch?v=KH9SCbCBHaY

That's the video I was talking about! Thanks M1key

 

[benzy2]

Right. It's just a theory.

Apparently you have never seen it, so you would never be compelled to try and explain it.

I do like cool videos, though. http://www.youtube.com/watch?v=KH9SCbCBHaY

That video shows the flight path does not stay in a straight line. It has nothing to do with multiple shots. Their model would show every bullet following the exact same path as well. Its also a youtube video, not quite your scientific standard. Either way it is just a model based on one theory of what is happening, be it true or not. I still don't see 1000 yard matches shooting better MOA than 100 yard matches, at least not in current recollection, but I haven't followed long range competition overly close.

 

[jon8777]

I had that Bushnell Elite 3200 10x40 scope, and it had slight parallax at 100yrds, terrible at 200yrds, never did find it parallax free. You've got one fine shooting .223, and if your scope is anything like mine, you must have a very consistant shooting technique to shoot past the parallax error

For $60 cheaper NIB than they were selling new online, I figured it was worth a gamble and it was 225$ cheaper than the scope I was looking at. I know its far from top shelf, not a Bushnell fan and I figured for a low recoil gun, I'd try it... so far so good.

X MOA could be thought of as a circular area with diameter = X MOA in which the bullets are landing. If you shoot 1 MOA groups at 100 yards, your bullets are landing in an area of 0.861 in^2. However, the area of a 1 MOA circle at 200 yards is 3.45 in^2 and at 300 yards the area is 7.75 in^2. So the area is a function of the square of the group diameter (nothing new here). In other words, if you shoot 1 MOA groups at 300 yards (3 times the distance), your bullets are landing in an area 9 times that of the area enclosed by a 1 MOA circle at 100 yards!

Thats actually a good point... guessing this isnt 1858's first run around the block

 

[DaleA]

It's late, I'm tired but here's a thought somebody else must of thought of before...
line some targets up directly behind each other at 100, 150, 200 etc and fire one group...if the group is 1 inch a 100, 1.5 at 150 and 2 at 200 that's kind of what you'd expect...if the groups at the longer ranges are tighter...well I guess that would lend weight to some of the theories posted here.

 

[scythefwd]

Aim small, miss small. That 200y target looks 1/2 the size of your 100y target? If so, you are holding on a smaller target, and probably being more picky about when you let fly.

 

[oldfool]

I have to throw my vote to "aim small, miss small", also
(which is same as I would interpret the above target ''comparative area" version)
a pretty universal phenomena, tight shooting is a mind game, mental focus, psychology.. not what the eye sees, but what the mind sees

I often shoot tighter when crosshairs literally obscure the target POA, rather than looking for center of a target... either it is fully covered, or it is not, no wandering/wondering about it, no "forgetting" to focus on the crosshairs not on the target, because they are one and same

the statistical argument posed up-thread would be suspect #1, but I think shooter is not referring to the posted one-time sampling, but a far larger sample of repetitive, consistent results over a far far larger sample size

"going to sleep" bullets is intriguing theory, but I see no reason to stretch for such rationalizations given the many subtle variables already in play... variable #1 always being mental

 

[jmr40]

A couple of points I would like to add. I make my own targets. I cut out a template and color in 1/2" squares for my 100 yard targets and 1" squares for my 200 yard targets. To further reduce the chance for aiming error I place the crosshairs only on 1 corner of the square. This eleminates the possibility of the aim small miss small theory. With some of my rifles I shoot consistent MOA at all ranges. With others I consistently see smaller MOA at the longer ranges. The difference is not great.

I'm just a hunter who likes to shoot, not a long range target shooter but with some rifles I will consistently see .75-1" groups at 100 yards and 1"-1.25" groups at 200 yards. I will sometimes get the .5" 100 yard group but it only happens enough to call it lucky.

It has happened to me too many times for me not to believe something is going on other than just "aim small miss small"

 

[3:00hold]

The "bullet going to sleep" theory can be tested very easily. Measure the hole at closer ranges and compare that to the hole at longer ranges - of course you would need to shoot something that allowed for this i.e. left clean holes. The only way that would be possible is if the bullet was vibrating or askew earlier in it's flight path and therefore left a bigger hole.

I'm an engineer, not a physicist, but I can tell you with 100% certianty that there is no way for a certain number of unguided bullets (let's say 10) to diverge from the perfect flight path DIFFERENTLY at closer ranges and then miraculously return to a common point down range. If they all diverge the same way, then the group would still be smaller at closer ranges. The example I described above would be the bullets maintaining the same flight path, just vibrating or turning slightly and leaving a differently shaped hole at closer ranges. Of course, we would be talking about a differnce in the hundredths to thousandths of inches.

There are only 2 ways to get smaller groups at longer ranges. 1) the bullet is guided 2) the hole at closer ranges is bigger.

For what it's worth, I don't think 2 is possible. That would be like a football quarterback throwing a duck at 20 yards that straightens itself at 40 yards.

 

[oldfool]

heckifiknow
but even though OP has apparently shot a lot of groups and seen consistent repeatable patterns, he might (?) be shooting only very few at any one sitting, as in post #1

IF in the habit of always shooting same sequence (100 yards 1st, then 150 yards 2nd, then 200 yards last), AND always starting with a clean barrel, AND shooting so few rounds per session (even though waiting for barrel to go cold between shots), the answer is intuitive enough...

but that's a whole lot of IF stacked up
unlikely the fellow would be doing that

 

[ArthurDent]

I am intrigued!

Apparently (post #29), the results are consistent! So much for my guess!

Aim-small, miss-small would be my next guess, BUT...

The possibility of this "going to sleep" thing has me fascinated!

BTW, I've NEVER seen this... just the opposite in fact, but I mostly shoot .22's, and never at longer than 100yds. (That's all my range has.) Usually the .22's will group nicely at 25yds, will spread out some at 50yds, and will be at 2 to 3 times the MOA reading at 100yds. (That's right, 12-times the actual, on-target spread at 100yds!) Only on a couple of really calm days has my MOA at 100yds approached my MOA at 25yds. (Yes, the .22 is a wimpy round.)

(grabbing my popcorn and waiting for more...)

 

[jmr40]

3:00hold.

A football will sometimes start out wobbling and then return to a tighter spiral. Been coaching high school football for 30 years. I've seen it happen more often when the ball is punted than thrown.

A spinning top will often start out wobbly and stabilize into a tight spiral. As they slow down they will start to wobble then correct its self. They will eventually slow to the point where they are no longer stable and fall.

We all know that different bullets stabilize best when the rifling in the barrels is correct for the bullet. Often slower loads produce better accuracy than faster loads. I could see a bullet leaving the muzzle traveling too fast to be stabilized by the rifling and after slowing a bit becoming more stable. This is also why I think the punted football is sometimes less stable at first. It comes off the foot much faster than when thrown and stabilizes after slowing down.

While we cannot see it, and I have no way to prove it, I cannot see why a bullet in flight might not do the same thing.

You are correct in that there is no force that would pull the bullet back to the point of aim. But if all the bullets in a group became stable at the same point in their path, They may well group into a smaller MOA (not actual group size) at longer range than at shorter range. The point of impact may well be farther left, right, up, or down than expected.

I don't offer any of this as proof. This is just a theory I've come up with based on my own observations and reading others comments. I simply don't know, but this makes sense to me.