Dot Amplitude -- how to pick the best spot over a barrel to locate a red dot sight.

Maybe I just have too much free time.  Maybe I ought to stop thinking about things, and do something useful.

Anyway I noticed while dry-firing (one handed) that the dot always moves around more than if I have two hands clamping the gun in place. Presumably, what the dot is doing, is mirrored by the end of the barrel which would be doing the same thing.  If that movement (wobble) were reduced, the group size ought to also be reduced.  (There are probably lots of explanations for this, but they're all pretty much irrelevant - if I want to shoot Bullseye, my left hand has to be parked in my pocket, rather than doing something useful.)

I've gotten into the habit of mounting my red dot sighs as close to the rear of the gun as possible because it makes my gun "seem" lighter.  It doesn't change the actual weight of the gun, but because the added weight is so close to my hand, the "leverage" minimizes the additional force that my hand(s) is/are supporting.  I got to wondering what the effect would be were I to move the red dot sight further away from me.  Specifically, would the added weight towards the front of the barrel "dampen" the movements of my barrel?

When looking through the optics while dry-firing, the "movement" of the dot in front of my bullseye target does seem reduced. 
Maybe that's real, or maybe it's just wishful thinking.
I thought I'd ask it as a question here, because there may well be other things I'm not yet considering. 



When a bullseye shooter mounts a red dot sight to a gun, what reasoning might he (YOU) use to decide where to locate the sight?

(There are other factors to consider, such as whether the image in the sight is better closer to your eye or further away.  I'm sure there are others I haven't yet thought of.)


To be specific, as a test, I moved my Aimpoint H-2 from the rear-most position to the front-most position on my rail.  
What changes is this likely to create, if different from what I described up above?
How does one determine the optimum location for a red dot sight?

over your hand is always steadier than on the muzzle.
They put those grooves in the back for a reason.
Don't go Pardini mount on us!!!

Pardini mount??????

Switched the dot location on my SSP in my avatar pic from the front of the pistol to the back and my scores went up quite a bit since. I am almost to the point where I think I know what I am doing on the firing line now

mikemyers wrote:Pardini mount??????

mid gun like in your pic

Since the gun is pretty much all set, I'll try it this way tomorrow (Sunday).  If it makes no difference, it will take me all of two minutes to move the sight back to where I originally thought it belonged, using the rear-most slot in the rail.  

I'm getting better at reducing the amount of wobble, and I'm real sensitive to the size of the wobble vs. the size of "the black".  Holding the HS with one hand is almost as good now as using two hands, so that's progress.  Lots of dry-fire and three or four visits to the range is my "prescription".

There are two Bullseye shooters at my range who I only see on match days.  If I get the opportunity, I want to see if they can give me some helpful feedback, based on what they see me doing.  

Meanwhile, I think the answer for my question is going to be just what I asked Alan to do for me, make a rail that will allow me to hold the red dot sight as low as possible, and towards the rear fo the gun.  Both Alan and Roddy set my guns up so I could do this.  Roddy's gun I hope to try out with steel sights, and see which I do better with, steel or optics.

I say put it wherever you are the most accurate. Then use that confidence and don’t worry about it again. Try it forward, centered, and rear with dry firing. Document your thoughts (movement pre shot, movement of the dot when the hammer falls, etc). I say use that to decide for yourself versus what others may feel/ think. 

I said on another topic that I am a rep for MantisX, although I don’t do any sales. I’m just a user/ believer that they seemed to like. I feel like I need to say that even though my recommendation is purely because it’s what I did. I’m an analytical thinker sometimes too (maybe not to your degree lol). I used the old Mantis device before I got the newer one for questions such as yours. I liked the arched MSH because it was more comfortable. So I decided to do 100 rounds of slow dry fire with flat and arched. My results were substantially higher with the flat MSH. So I kept that on and never looked back. Same “experiment” could be done with placement of scope, trigger length, grip changes, etc.

'dapduh2 - you're correct about the way I think, and after this morning's experiments, I completely agree with what you wrote.

Having shot between 50 and 100 rounds yesterday with the sight at the rear, this morning I've been dry-firing with the sight in the new position.  An hour ago, I went into my kitchen and dry-fired against a dark wall.  The red dot was quite small, and at one of the lower brightness settings, so I could easily see any movement.

As I think was suggested here long ago, the area at the rear of my right thumb was pressing hard against the gun.  The area below that not so much.  On the front of the gun, my trigger finger was applying constantly increasing pressure, and the finger below that was pushing back, against the area below my thumb.  I noticed that sometimes the "dance" that the red dot was making was more round, and sometimes more vertical than horizontal, which intrigued me.  It turns out that if my right thumb was touching the side of the grip, the pattern of the dot became more vertical.  (I noticed this yesterday, but had no idea why it was doing so.). The least amount of movement from the dot was when my right thumb wasn't really touching anything - and if I barely let it touch the top of the thumb-rest on the grip, things stayed good, and I felt more comfortable (maybe from "knowing" where my thumb was).  For 100% of my dry-fire, when the gun went CLICK the dot didn't do anything different - the "dance" remained the same.

My impression was that with the sight moved forwards the way it is in my photo, the red dot dance (wobble) was the smallest.  So I need to try this at the range, then move the sight back, and compare.  I don't even need to sight-in the gun - the only thing I'm testing is for the group size, which should be directly proportional to the wobble.  


I don't know much about MantisX.  I've never seen one, let alone tried to use one.  You said the device is useful for questions such as mine - maybe sometime I'll be able to test how sensitive it is.

dapduh2 wrote:........I said on another topic that I am a rep for MantisX, although I don’t do any sales........I used the old Mantis device before I got the newer one for questions such as yours......Same “experiment” could be done with placement of scope, trigger length, grip changes, etc.

Not sure if this device will tell me more than I can already "see" while watching the red dot during dry-firing.  Quick question - if you already have a red dot sight that will be mounted on the rail, where would the MantisX go?  Ahead of the sight, or behind it?  Do they make a simple version, suitable only for dry-fire?  I do see lots of ways to "experiment", but I think I'm already doing that just by watching my dot.   Maybe sometime in the future I'll want to buy one, but for now things are already coming together.  

My trip to the range didn't happen today - there's a match going on, and by the time that's over it will already be quite late.  Tomorrow (Sunday) there is a Combat Match - It will be finished by very early afternoon.  Monday on the other hand, is a very quiet day at the range, and I can be there all morning and a good part of the afternoon.

For the past few days, I've been dry-firing with the sight still moved towards the front.  I think I have a pretty good sense of how much movement I get in the red dot.  Based on what I've already found out, I might just move the sight back towards the rear.  If nothing else, Jim won't be laughing at me.   :-)

The devices are small, could be mounted behind, in front or wherever you like. I use a temporary rail under that attaches to the trigger Guard. Mantis also has mounts for the bottom on magazines that work. And yes, they just released a dry fire only device. I haven’t looked into it though.

If only you had bought a Benelli!!

Big Jim. The 3D printer Master

Gack!!!!

That is so NOT me!

(I moved the H-2 to the third rail slot from the front.  
The dot amplitude got smaller, not larger.  So much for my theory...)
I think the more I dry-fire, the smaller the dot dance.

I also removed the rail from my Victor, and put the steel sights back on.
So much lighter.

I have worked with the position of the dot on many of my guns. Each gun has responded a little different as expected. My only conclusion was as the dot moved forward the arc of movement seemed to speed up and as I moved it back the arc of movement slowed down. Amazing on how that works. I settled on a dot near or just slightly forward of the trigger. This seems to "connect" the dot/trigger and produces the best groups for me.

mhayford45 wrote:I have worked with the position of the dot on many of my guns. Each gun has responded a little different as expected. My only conclusion was as the dot moved forward the arc of movement seemed to speed up and as I moved it back the arc of movement slowed down. Amazing on how that works. I settled on a dot near or just slightly forward of the trigger. This seems to "connect" the dot/trigger and produces the best groups for me.

My intuition said otherwise, but from a lot of dry-firing, I can see that you are right.  I originally thought that more weight up front would have slowed down the movement, but maybe because of inertia, the movement was greater.  When I put the sights back where most people suggest, the gun felt more stable.  I'm guessing that the movement I see is mostly due to "tremors", just like I see in the viewfinder of my camera.  There is almost always some movement.  Then I read that the best way to deal with that, was to ignore it, so if my gun wants to "quiver", the only thing I'm paying attention to is that the gun doesn't move because of my working the trigger.  At any rate, this is what I ended up with.

I'm also wondering what effect barrel weights have on all this.  I've read that they are to reduce the amount the barrel moves upwards when you fire.  Do they have any other effects, good or bad?

For anyone comparing my older and newer photos, you'll see the polarizing filter is back on the front of the sight.  Shooting targets in bright sunlight made the "white" in the targets much too bright.  The filter turns down that brightness, but doesn't have any effect on the brightness of the dot - although the dot does "seem" to be brighter.

To me, what feels the best, is to have nothing on top of the gun other than the rail and steel sights.  That's something else to work on.  Maybe in April or so, I'll be able to try that out on the X-Series.

Everyone I know including Brian Zins has dot movement. It seems that most humans have varying amounts. If the muzzle is moving and the dot is out at the muzzle then you get the most arc of movement in the dot. Just physics at work. So, if you add weight at the muzzle and the muzzle is moving then as the weight increases it takes more force to stop and move it in a different direction. Again just physics at work. So, there will be a weight that will destabilize your ability to overcome the movement. The additional weight can help with recoil management to a point. 

For me, I like the additional weight just in front of the trigger. Muzzle weight beyond an ounce destabilizes my ability to hold SF and I have low shots with larger group sizes. This is one of my complaints with the Pardini as they are very muzzle heavy. 

I also like Aimpoint Micros or Holosun Micros over Ultradots as they are lighter and can be moved forward and backward to tune weight. The ultradots are not as tunable.

Major improvement!

I got my new High Standard X-Series to allow me to shoot better than I could with the iron sights on my Victor, which is why it was mounted as shown in the above photo.  I didn't like the massive (and heavy) mounts, so I replaced that Ultradot with my Aimpoint H-2.  I don't know "why", but even though I can clearly see the front sight with the proper glasses, my groups for the most part were better with optics.

Back to the Victor - last night I removed the steel sights, mounted the rail that Roddy made for me, and put the Matchdot II from the above photo on it - and again realized it just weighed too much.  So it came off, and I mounted a Matchdot II with the stock aluminum (?) mounting rings.  Much better.

Went to the range today, and after an hour or so I wanted to sight in the Victor.

I can understand, and accept, that I get to see my "wobble".  Dave Salyer tells me to just place my wobble in front of "the black", and to not concern myself with the wobble.

What I was dealing with for much of today was a dot that moved back and forth in a straight line, so fast I couldn't even begin to follow it.  Every so often it might stop, but then it started back up again.  So my shots included several "wild" shots, probably because of this.

I sat down at the table, and tried to think of what could be causing it.  The best answer I could think of was "resonance".  That's where an out-of-balance car tire might roll smoothly at most speeds, but at one particular speed, it will go wild and vibrate.  It's also why if you hold a cup of water or tea, and move it back and forth, it might leak out a little, but there will be one speed where the movement will go wild, and water will spill our all over.  It's like a swing set in your back yard, where it runs smoothly back and forth at one speed, but you can't really make it go slower or faster. 

My conclusion was that something in my body, my heartbeat, my breathing, the weight distribution, how stead I am, or am not, was reaching a point where the dot was oscillating back and forth VERY rapidly, and moving back and forth more than just my wobble would cause.

Option 1 would be to add weight to the front of the gun, but I had no way to do that.  The gun already has a barrel weight - maybe I should have tried to just remove it.  Option 2 would be to move the sight towards the front, as I had done with the Aimpoint, but the Matchdot II doesn't move all that far.  Option 3, the only one I was able to try, was to loosen the sight mounting screws, and move the entire sight assembly forward.  Here's what I ended up with:



The next time I tried the gun, I was amazed.  The problem of the dot dancing back and forth in a straight line as if it was attached to a vibrator, was gone.  I still have my wobble, but I've learned here to just accept the wobble, and ignore it as best I can.  The "wild shots" heading for Mars or Venus went away.  

I had a bunch of leftover ammo on my bench, fired that off at the end of the day, after sighting in the gun. The target below is nothing to brag about, but it put me in a very good mood, as it's just a normal distribution of shots, nothing strange or wild.  No shots on their way to outer space, either.  I will be totally, completely, pleased if all the rounds at 25 and 50 yards just stay in the black.  I still think it's possible.  With that "vibrating dot", where the hole would end up was as much due to luck, as to anything I can or dan't do.

mhayford45 wrote:Everyone I know including Brian Zins has dot movement. It seems that most humans have varying amounts. If the muzzle is moving and the dot is out at the muzzle then you get the most arc of movement in the dot. Just physics at work. So, if you add weight at the muzzle and the muzzle is moving then as the weight increases it takes more force to stop and move it in a different direction. Again just physics at work. So, there will be a weight that will destabilize your ability to overcome the movement. The additional weight can help with recoil management to a point. 

For me, I like the additional weight just in front of the trigger. Muzzle weight beyond an ounce destabilizes my ability to hold SF and I have low shots with larger group sizes. This is one of my complaints with the Pardini as they are very muzzle heavy. 

I also like Aimpoint Micros or Holosun Micros over Ultradots as they are lighter and can be moved forward and backward to tune weight. The ultradots are not as tunable.

Two quick thoughts.  First, all my shooting lately has been done following Dave Salyer's advice on "Area Aiming".  I'm no longer trying to "hit the bullseye", just get all the rounds in the black.  I'm also shooting at a "sustained pace" as Dave called it - I'm pretty sure I'm shooting at a Rapid Fire pace.  I will bring my phone to the range today, and play the range commands for Rapid Fire, and see if I'm shooting quickly enough.

I know everyone has dot movement, but I'm referring to something very different, "natural frequency of vibration".  Early yesterday, I had two issues - dot movement, and also this "vibration" problem with the dot moving back and forth in a straight line, so fast all I saw was the blur.  From what I know about vibration, if I change the "system" (gun + me), so my natural movement is being picked up differently by the gun, that "vibration" ought to go away.  It did.  I suspect if I wrapped a five pound wrist weight around my wrist, that would have had the same effect regarding the vibration.  I will test this sometime soon.

If you had an out of balance tire, such that it vibrated and shook very much at say, 50mph, changing your speed to 40 or 60mph would eliminate it.  I've had that happen.  In my case, I assume my body was doing something, movement of some type, that this was somehow causing the end of the gun to shake right/left at a VERY fast pace.  Moving the sight the way I did eliminated the "vibration", and just left me with a normal wobble, like I get from all my other guns.


I'm only concentrating on one thing at a time.  I'm not thinking of slow fire and the issues you noted.  That may still be another issue for me.  I'm not going to even think about this for a while.  Dave tells me that if I can get all my shots in the black (which he says most shooters can't, so maybe I won't), that is good.  If there was a match tomorrow, I would shoot SF, TF, RF, at this one pace.  


Back to what you wrote, I wish that was my only concern.  I understand what you mean about the weight issues, as that is very limiting to me.  Once the gun gets too "heavy" for me, my whole hand starts to shake just from holding it up.  Because of that, I try to use lighter sights, and I again started doing "holding drills" (aimed at a blank wall, NOT a target, as CR posted a while ago.  I'm probably also going to start Physical Therapy, to build up some of my muscles that used to be stronger.  


Last thought, after re-reading your post.
You wrote:  if you add weight at the muzzle and the muzzle is moving then as the weight increases it takes more force to stop and move it in a different direction


Completely true, but it also means:
if you add weight at the muzzle and the muzzle wants to start moving, then as the weight increases it takes more force to start any movement.

To me, I think that means I'll have less movement.
If I taped a brick to the end of my barrel, I don't think the barrel would move.

Gravity would accelerate the brick, gun and arm down. Just physics. Also, I tried the Dave Salyer advice on area aiming for several years and ounce I abandoned the advise made master. He also told me that a cross dominate eye shooter, such as myself, would not make master... So, my point is to try different things and use what works for you. Might I recommend Bullseye Mind by Raymond Prior, PhD.

Gravity might try to do a lot of things, but presumably the shooter would be using his muscle strength to hold the gun up.  Just an example, I didn't think anyone would actually put a brick on the end of a barrel.  Just saying if all that weight is there, a little bit of tremor in the shooter's arm or hand would probably be undetectable at the muzzle.

Curious, what did you do, to follow Dave's advice, and what didn't work?  

When I am trying to do well, and I aim at a spot on the target, I hit all around that spot, but nothing ever hits it.  I can create a pretty donut made of bullet holes.  Dave says that is because by the time you fire, the gun will have moved.  On the other hand, it you're just trying to get all your shots in the black or something similar, you'll end up with a "bell curve" for how the shots are distributed, and the majority will be in the center of the aiming area.  

I try lots of things - what still works best, always, for me, is "area aiming".  I'm also up in the 70's, and not all that strong to begin with.  The first time I tried to hold a 1911 in front of me with one hand, I couldn't!  I think years ago none of that stuff bothered me so much.  My heavy guns didn't "feel" heavy to me, back then.


What is "Bullse Mind"?
https://www.amazon.com/Bullseye-Mental-Toughness-Shooting-Paperback/dp/B07CTZJ79H 
A used copy is $60.00 .....

In what way did it help you?

If it's similar to "With Winning in Mind", I'll pass on it.

(Between learning how to use a new Leica M10, learning the editing software I now use, all the computer stuff I'm involved in, I think I'm going to slow down on all the Bullseye stuff.  I've been going to the range five or six days every week, plus dry firing.  I didn't expect to ever get as good as I've gotten, but I see a long ways to go.  As long as it's enjoyable, I'll keep at it.  Dave and you guys have helped me get to a place where I can do things reasonably well, and still enjoy myself while doing so.  I don't want to get to the point where all of this starts to feel like "work", rather than a hobby I enjoy.  I ought to stop asking for help and advice, and just go out there and "do".  That other book, "With Winning in Mind" might actually be helpful, but I have no intention of devoting my whole life to shooting, at the expense of all the other stuff I'm doing.  I used to just take my revolver and a box or two of ammo to the range, and enjoy shooting.  It didn't cost much, either.  My new Leica has minimal computing built in, if I want a good picture I need to do all the settings and other work.  Then, since I'm shooting in "raw", there's a ton of work in either Lightroom or DarkTable.  I enjoy that too.  I think learning to be a really good photographer is at least as difficult as learning to shoot well, maybe more so.    :-)    )

I believe that what helped me most was to stop "thinking" have a trusting mindset, focus completely on the current shot, Not worrying or thinking about my score, eliminate what does not produce 9,10s and simplify my process. Much of this is covered in the Bullseye Mind book.     

Bullseye Mind is available at www.rfpsport.com 
It is not similar to mental toughness or with winning in mind

I am 65 and I think that I have not shot my best score yet.

Never mind my previous post - I need to get back to just going to the range, and enjoy my time there.

Still, I'll add another thought, that "vibration" that bothered me so much was also present in dry-firing, and my other High Standard, my new X-Series, doesn't show what I was referring to as "vibration" at all.  It just has a normal wobble.  Oh, and a friend at the range let me try his Volquartsen 22, with a barrel that looks so long I think of rifles - I shot his gun about as well as I shoot my own.  I like the gun, but my HS guns feel more comfortable in my hands.

'mhayford45', I tried to "stop thinking", but after some feedback about that here, changed my shot process a little.  I found if I grip the gun slightly differently (doing this as Brian Zins suggested, with my hand wrapped around the gun, but the "base" of my hand a little more to the right, the gun nice does what Brian said it would - it ends up naturally pointed right at my eye, not the bones in my arm.  I figure that's good.  Also, relaxing.  

My plan for my next few visits to the range are to just shoot at white paper, no bull.  That, and relax more.  Oh, and start using some of my other guns.


Only one question....   how is it possible to " eliminate what does not produce 9,10s" if you don't know why they happened?  :-)

(.....and I am 99.999% sure "what happened" was that I moved the gun as I fired.  I'm gonna stop worrying about that, and just get so used to dry-firing, that hopefully the problem will go away, since the gun never "moves" when I dry fire.  The red dot, against a blank wall, now stays perfectly still.  Maybe at the range, I'm tensing up, 'cause I know the gun is going to fire.  Maybe I'm gripping it more tightly without realizing it.  Maybe I'm not as relaxed as I am at home, dry-firing in my apartment.)

Enough of this, I'll check out the link you posted for Bullseye Mind.  Hopefully it is available at a more reasonable price.  Thanks!    :-)

I picked up a copy not too long ago from here.  $17.95

https://www.creedmoorsports.com/product/BK-BEM/Books-CDs-and-DVDs

Hmm, the link didn't work, but typing it in manually worked fine.  I started to fill out the form, but they only take paypal which I no longer have or use.  At least the price was reasonable.

DA/SA, I'll try your link.  Thanks!

Order placed.