Head position vs absolute aperture height

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InTheBlack

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Here's something that might be part of my difficulty in high power prone. Since I have only shot at 100 yards, I haven't given any thought to the height of the rear sight and its effect on how much you have to tilt your head forward to get your eye lined up.

In _The Competetive AR 15_ Lew Tippie has a chapter, and on pg 265 he says he likes to adjust the front sight height so that the rear sight is about 20 clicks up from the bottom for the standing position (quarter minute clicks).

Now my gun is basically the way Bushmaster sent it to me, and I don't need to change the elevation for the 100 yard reduced course. The half-minute sight is 12 clicks up from being bottomed out (on the number "6"). I might change for light, but not much.

I'm beginning to think that my rear sight is very low ???

My sight is 25 clicks/revolution. How many clicks/rev is a quarter minute sight?

Tippie says his slow prone height is about 70 clicks from the bottom. That would be 35 clicks on my sight vs where it is now at 12.

Zedicker (pg 88) makes the point that a lower aperture makes it easier to deep "decent face pressure against the stock" and recommends "more like 15" minutes at 600 yards. That would be 60 of Tippies clicks, so I guess they are both in the same ballpark.

Match tomorrow; maybe I'll raise the front sight a couple of revolutions (=9.6 MOA) and bring the rear up to about 32 clicks.
 
U R Thinkn too hard.



Not a lot of levity here, gotta have about (depending on the shooter) 12 minutes of elevation between your 200 yard setting and your 600 setting. If you have a match front sight, you don't' have much of a choice because the thing is only supposed to point one way (sight is angled at the top so you always stop with the tallest point toward you). That means you may be 4 minutes too high or low (at the extreme) from what you really want but you gotta deal with it (A2 sight has a 5 minute revolution). My 200 standing is a 4 clicks from bottom and my 600 center hold is 50 clicks up.


Neither Lew nor Glenn told you whether they held 6 o'clock, flat tire, or center, OR what the dimensions of their faces are, did they?

Don't stress over the little stuff.

If you are 12 clicks up on a 1/2 MOA sight (total of 6 clicks) you could rotate the front sight down one rev exactly and should be at the same place, giving you two clicks up for a 100 yard zero (6 or center?) You will add to that for your 200 zero, but I don't shoot at 100 at all so I my sights won't even do that without a front sight movement. Whether you need that 100 yard capability is up to you.

If you have a 1/2 MOA sight and I have a 1/4 MOA sight I will have twice the clicks that you will.

quote:

Tippie says his slow prone height is about 70 clicks from the bottom. That would be 35 clicks on my sight vice where it is now at 12.



Umm, he is talking about shooting at 600 yards, not 100 as you had referenced earlier here :

quote:

Now my gun is basically the way Bushmaster sent it to me, and I don't need to change the elevation for the 100 yard reduced course. The half-minute sight is 12 clicks up from being bottomed out (on the number "6").



Pay no attention to the numbers on the drum anymore. You need to start counting clicks only. Now, I don't know what the change from 100 to 200 is, bu I do know that a good "in the black" rule of thumb is 3 minutes from 200 to 300 and 9 minutes from 300 to 600. That means 12 minutes or 24 clicks total on your gun (48 on mine) from your 200 yard zero to your 600 yard zero. Now, if Lew starts at 20 and adds 48, what does he get? 68 clicks, which is only a 1/2 MOA off what he said he is using (70). I start with 4 for standing and add 48, that gives me 52, a 1/2 MOA off from what I use at 600 (50). I am 5'7" on a really tall day, so I don't think I'd do myself any favors by stretching my neck out by raising mine to 20 clicks for 200 yards. The 1/2 MOA here or there is inconsequential, as we all look through sights differently.

BTW, if you take your 12 clicks, add 12 MOA, you get 36 clicks up form bottom, which is right where you interpreted Lew's comments to say.

SO. You can stick your front sight wherever you want, as long as you are comfortable and you have enough height for 12 minutes of change. Make sure you have some upper buffer for weird days.

No offense, but I'm betting you bit the big one with your 600 today. If I'd had been your coach I'd hit you with a stick when you reached for that front sight tool. Get your sights where you can shoot the whole range without moving the front sight. Only move your rear. Every time you move off the line, count your clicks OFF, and then count them ON for the next firing line. I always wind up doing this again at the next line because I want to make sure its right.

BTW, not surprising that Lew and Glenn are very close...everyone that shoots this game with 80 Sierras will be right there. Others will not be very different themselves.

Hope this helped. :)
 
man you guys got me confused!
if I had to compute all that out I know I would mess up sooner or later.

now my rifle has 1/4 elevation with a custom pitch on the threads and 25 clicks per revolution but the threads are very fine so the sight does not raise alot.
now I have seen bushmasterts and rockrivers depending on how the sight is set up as what you get with 25 clicks.

now if I do the following this is what I shoot one way or the other with the first choice coming first.

200= 6 to 8- 1/4 clicks for a 6 hold at 200 yards
300=down to 4 - 1/4 clicks to get me to center hold at 300 yards
600= up 39 -1/4 clicks for a center hold at 600 yards
so I always start from dead bottom and count up at each range or yards.
so its this
200 up 6-8 from bottom 6 hold
300 up 4 from bottom center hold
600 up 39 from bottom center hold

now if I decide to shoot center for 200 yards I need to go down one revolution on the sights which is up on the post and then my sights are now like this:
200 up 15 from bottom center hold
300 up man why do this to your self go out and shoot and get your setting down.
if you start to worry about what each different shooter does then you are going to go nuts because most everyone shoots what works for them.
 
The match results were great. I shot my best slow prone ever-- 6-X in a tight half-inch group, 6-10, 4-9, 2-7 = 185/200. The sevens were my first two shots; on my sighter I saw an old hole way left in the white, and didn't see the actual hole in the black-- so I screwed up my windage and had to correct on the first two record shots. Need a better scope !!!

Raising the front & rear sight so that the rear aperture is physically higher puts my head in a much better position. I'm not struggling with peering out from just under my eyebrow. I didn't get neck strain halfway through the string. I'm about 5'11" tall.

I'll go over your come-ups and figure out if I have enough elevation to shoot a real 600 yard course. But I think I ought to, because basically I'm at the same rear aperture height Zedicker and Tippie use.

Is there much elevation difference between a 69gr Sierra and an 80 gr? Really moot, since if I ever get to shoot at 600 yards I'll go out and buy some 80 gr for the long line. I really ought to be using those 52gr flat base for the 100 yard reduced course, but what the heck.

Part of this is the fact that I spent half a day just looking thru different prescription powers and aperture sizes, and I used a slightly less powerful than normal contact in my right eye so I could focus on the front sight better.

I shot 93 and 91 in the rapids. Some stringing, and windage off to the right (from messing with the front sight height). Probably lost 10 points due to the windage error.

Overall score 435/500

I only got 7 shots off in slow standing, because I couldn't scope the target to see where it was hitting and I knew that raising the front sight had slightly moved the windage. It was so humid that my breath was condensing, and between the fog on my glasses and on the eyepiece, and the fact that I need a bigger scope to gather more light, I couldn't find the bullet holes. Total 66.

My first 4 shots were all 10s, then I had to hurry and shot 9,9,8 and then I was out of time. I refuse to just blast away, because I won't learn anything from it. Even though shooting as bad as 3-5's would have raised my match score to 90%, which is what my current goal is. If I were able to see, I'm sure I would have scored at least 90% in standing.
 
Ok, so you shot another 100 yard match, and that is good because you didn't "bite the big one" at 600. Before you go to that distance, get yourself a sight setting that keeps you from having to change the front sight during a match. If you have to make a change you're asking for a disaster one day.

Difference of 69s and 80s? I dunno, never fired 80's at 200 or 300, and never fired 69's at 600. lol

Where are you? Don't have any 600 yard ranges around?
 
if I fire hornady 75's at 600 with a center hold I'am 57 -1/4 minute clicks up from dead bottom
now with 80smk's at center 600 I am only up 39-1/4 minute clicks from bottom

thats 41/2 minutes of elevation between the 2 different type's.
to me thats alot.
after 300 yards those 68,68,75 and 77 grainers will drop quite alot
 
I'm near Aberdeen Proving Ground, so the nearest 600 range would be Quantico, unless they start allowing civilians at Ft Meade again.

I'm looking out for clubs that might have a 200 or 300 yard range in southern PA.

Understand about not wanting to change the front sight height _ever_.

I think I'm gonna have to get into the $600 range to get a good enough scope :(
 
You mean the Swift Nighthawk? I have a Lynx 60mm and it has nice clear optics; but its not gathering enough light to see the 22 cal holes reliably.

Snipercountry.com did a range-test of several scopes including the Nighthawk and it did just as well as the bigger names.

I'm thinking I need a LER eyepiece more than a variable. Which is good because the variables are a lot more expensive.

http://www.hotbuysbinoculars.com/swift_spotting_scopes.htm

July 2003

Swift Nighthawk 80mm angled 45° Spotting Scope BODY ONLY $435.98

Swift Zoom 20-60x For Nighthawk Scope Eyepiece $185.98

Swift 19x For Nighthawk 60.98
Swift 25x For Nighthawk 60.98
Swift 31x For Nighthawk 60.98

Also asked the Snipercountry PX and they can supply the 75mm Hermes with the 30x wide angle eyepiece for about $600."The 30x is a wide angle eyepiece. It has an eyem relief of approximately 17mm" This is an IOR/Valdeda scope, Czech optics.

Have to see if for the same money a Kowa LER eyepiece might give more relief.

Might be time to start a scope thread...
 
Yes, I bought the Swift Lynx because it had the largest eye relief of any 60mm 45 degree scope I could find. Eye relief is 33mm at 15x and 25mm at 45x. There is a bigger physical comfort difference in 10mm than one would expect.
 
Sorry, I'm doing two things at once..missed that you already have a Lynx.

It isn't gathering enough light at 100 yards? I'd heard that they are much better than that.

10mm makes a big difference, I know.

Doesn't seem like there's much of a price difference between the Hermes, the Swift Nighthawk (when coupled with an eyepice) and the Kowa 661. I can say that the 661 is plenty bright. I can sometimes make corrections mid string based on what I see in the scope during rapid prone at 300 yards.
 
do not get to worried because at 200 yards in a heavy heat its hard to see .223 holes with the best scope money can buy.

I have had trouble even at a 100 yard match in the heat of the summer.
but you will sooner or later get to see where you are at on the target.
sometimes you have already dropped a few points but can move on by then.
if you have your slow prone position down enough to make slight adjustments thats great but if you are having a problem seeing the holes at 200 or even 100 then you are having lighting problems that are going to cause you to be high or low anyway depending on how you see the target between shots and untill you understand what the light and mirage are doing even at those short ranges you could be adjusting for a problem that is caused by light and conditions.
you ask why bring this up?
well at your own 100 or 200 yard range you should have your zero's down anyway to the point you just put it on the rifle and get with it.
if you have lets say out of 20 shots a group like this:
5-x's
7-10's
6-9's
2-8's
now looking at the target you see where they are grouped. try it in practice.
you have a nice group solid in the 10 ring at 12 with a couple on the edge of the x ring and a coulpe on the 10/9 ring.
then you have that nice group of 4 -9's out at 12
and the 2-8's and 2-9s out at say 5.
what you have is a lighting problem causing you to have several different groups up to 3 or 4 group patterns.

with a good scope you need to adjust the middle group slightly down into the x ring and then worry about what you see in your sights to cure the rest of the shots that are out assuming your hold and trigger control is very good.

you most likely are using a 6 o'clock hold at 200 or 100 and the way the sights go will make the diference on the impact like this.
most folks like steve have the thinking and it is right for the them light up site up, light down site down. with me its lite up site down and light down site up because of the following.
when you get a condition this time of year like the following my rifle acts like this.
targets look just ok and you get a decent sight picture. I get a solid 10 or x.
target gets hard to see the fine line between the post and target my shot goes high.
target looks nice and clear and target looks great shot goes way low.
why well its the heat or lighting on the target that is causing it.
if you have your rifle zero's for elevation on the prevaling condition for lighting most of your shots will go right in where you want them.
now when that wind dies down and the mirage builds up almost into a boil or into a boil if you do not catch it and adjust or wait till it lays over the target edges will fuzz out slightly and this causes you to hold slightly higher with out you knowing it and the shot will go high.
now also when the wind picks up slightly more than normal you will get two effects the target is more plain so apears to look great and you find that line between the target and post real easy and what has happened is that the target has grown so you shots will go low and in this condition your shots will go lower than they will the other way with the mirage and also because of the mirage laying over because of the wind and the target growing you also have the optical illusion of the target growing oblong and thus your shot will be out low on the opisite side of the prevaling wind.

thus when you get your new scope buy a nice one when you can, it took me two years of using a 60mm c.c. till I broke down and bought the 821 kowa. yes it has saved me a few points off the c.c but the 661 will also do the same for you at 200 yards also.
in the spring, fall and winter when the conditions are nice the good scope will pay off big time as you will get to shoot and see the holes also but this time of year you ought to learn why your shot went down into the 8 ring at 5o'clock when you knew it was a good shot.
here is what happens with any scope good or bad and you can ask steve as he has the 661 in 60 mm and mine is the 821 in 80 mm both top of the line kowa's on a bad day neither one of us can see anything any more than the other guy.
now where mine really helps is at 600 yards and maybe 300 but not really at 200 and below. but if you are shooting at 600 you have pits anyway so ready conditions is where it really pays off.

yes you will make up more points at a reduced match with a good scope as it may let you see the holes a little faster than normal.

at 300 yards in the old days of 30.cal. you could almost always see the holes at 300 rapid but with the .223 I never look at the target anymore but the flags as it will get me a indication if I need to adjust my sights for windage or not.

good luck and follow steves advise on scopes as he does have a very good handle on it.
 
jc- Thanks for the details about perceiving the black vs mirage and light. the Owens book mentions this but not in so much detail.

When the black gets "fuzzy edged," can you actually perceive it when focusing on the target? How good is your vision?

My Lynx can see .223 holes in the black at 100 yards when the target is in the sun, but not so good in overcast and hardly at all in shade.

There don't seem to be any quality brand 80mm scopes in the $400 range. All the name brands seem to start at $600.

Why is it called tourist season if we can't shoot at them?
 
yes I can see the difference on the target.
do I always adjust for it, NO
but I do watch for it.
I wear perscription glasses to shoot with as my 49 year old eye's are not what they used to be.

know you might think continuing on this thinking along this subject.

lets say you are at 600 yards firing slow prone.
you idealy would only shoot in a known wind condition or as close to it as you can.
now when you get to a 100 or 200 yard match you kinda adjust slightly for the wind and then its off to the races for your slow prone.
when you can see the target and holes you try to adjust it to the middle of what you know as the center of the group and its most likely a given what that will be.
now most folks once they have shot for awhile and start to perfect the prone hold find that almost all the points they lose go out the top and bottom of the 10 (that also works as 600 also) once you get the wind down a lot better.
now as you say how do you decide when that is going to happen.
its like not pulling the trigger in off hand when you know its going to be a off shot. its all mental awareness and watching for it.

take this example:
lets say its hot and its a 200 yard match you start out ok but target is kinda hard to see and when you do on say shot 4 you have 2 -10's and 2-9's out at say 1o'clock.
now you adjust to center and off to the races you go. but now you get a peek at the holes again on shot 10 and you have 1 eight out at 6 at another 9 out at 11:30 but you know the shots were good and you say oh well and keep going must off been me.
have you ever noticed how your eyes might fatige and after you rest them for a few seconds the target looks alot better and you get that shot off. thats one of the same things you look for.
DOES that target line look exactly the same I bet it does not and you just thought it looked close.
take a 10 shot string of rapid prone, you start out first two shots are fine, change mags then next few seem fine and then your eyes start to get a little fuzzy (wind dry's them out, your tired or what ever the cause) so your last 3 shots go out the top for a 8 and 2 nines, same thing happens at slow prone but with the mirage fuzzing out the black instead of your eyes. so what do you normally do you aim slighty higher till you think you are right at the same spot and then the shot goes out the top.
you need to watch for anything thats not exactly the same on the target.
when you raise those sites and you find they are a little tough to see on that next shot STOP. then rest your eyes to make sure its not them and then get back on the shot and if it looks good take it.

it works the same as your zero's in the mourning compared to about noon.
your elevation might not of changed much but you will most likely notice you have to come right on your sights by the time you reach slow prone.
if you do not believe that next time you go to a 200 yard match the first couple of shots for most everybody will be to their left if the targets are to your north on slow prone on normal light days.
 
What I did at the last match was to shoot center of mass, and I noticed that I did better if I perceived myself as "shading it high."

My front sight is so much wider than the black that a six o clock hold doesn't give me enough perception to keep it centered horizontally.

Looks like the best price on the Kowa 821M is from
CREEEDMORE for $556 and the 27x LER is $137 = $693

Need to find the eye relief on the Swift Nighthawk lenses. That would come to about $500 with a 19x or 25x or 31x lens.
 
my opinion is that if you are going to spend $500 I would get the kpwa 661 or just fork out the extra $200 and get the 821.
does the cover come with the creedmore priced scope or do you have to add it to the price as you need it.
if you buy the scopes from owens (steve can get you the web page) they are dropped shipped from kowa directly to you and you get everything for one price.

I also shoot center of mass on my prone positions and here is what I find.
let me get back to you at work.
 
With all due respect to my friend Jon I don't see enough difference between the 661 and the 821 to turn around for the difference. If you are ina lot of shade, perhaps the 821 would be better because of its much larger objective lens. Here in Colorado we don't have that problem and I've never seen anything in an 821 that I could not see in a 661.
 
for the money steve's right about the 661.
I had the cash at t he time and just went ahead and got the 821. got used to the tsn series in 77mm years ago and wanted something its equal or better.
back in the days of the 30.cal it payed off seeing your holes at 300 yards between mag changes but with the .223 it really is a non issue anymore.
during the colder months and in the rain the 821 will get you more but how often do you really run into those days, not often.

now as far as using the center hold it should cure alot of those left to right strings as long as you continue to disect the front site.
if when you get your elevation down you should look directly at the center of your front post and then mentally put that exact middle of that post in the exact middle of that target and pull the trigger while concentraiting on the front post.
that should cure most of all of your left to right but even with a 6 hold you should be doing the same thing.
now the center hold comes more into play to help cure elevation changes but you have to really be carefull as most points are still lost to elevation due to the before mentioned problems but now its less of a factor and even has the opisite effect as the 6 hold.

you need to be carefull when you bring your front post up into the black as you will still get that target grow or shrink do to light as it is always going to be there.
but what you are going by now is that the center is alway going to be the center and you really have to remember that if the target seems smaller hold the center the same as if the target seems clear and bright.
after you have that perfect npa set on that shot and you bring the sights up into the black and find it hard to see where you are at you can do a few things like force the front site out slightly to the left or right and adjust the height of the post with your breath and then led it slide back into the center of the black, find the center of the front post in the middle of the target and since you have not changed your breath BANG you should be right there.
holding center will not always look clear to you but the center of that blur is still the center.
if you bring that front sight up and it looks real nice and clear at 600 yards lets say be carefull you do not have to much black on top of your post as it will cause that shot to dive low.
 
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