Scope Eyebox and positional shooting

[nycnoob]

I am having some trouble with my rifle scopes eye box. I do some
precision shooting (Appleseed and Highpower) and I can not find a
position on the rifle for the scope which gives me the
correct eye box for both prone and offhand. I have taken to
putting my scopes on a rail and moving them an inch or two as I
change position.


I do not understand why I am the only one with this problem. I
have taken Randy Cain's class and the others their had no
troubles with their scope mounts (but the whole class was using
Leopold scopes). I have been to Appleseed events where most of
the shooters were using scopes and they did not need to make
adjustments to their rifle between positions.


For highpower I am using the: Bushnell Elite Tactical Rifle Scope
1-6.5x24mm on a Tikka with an OEM stock.


For Appleseed I am using the Primary Arms 1-4X24mm scope on a
10/22 wooden stock.


I know that for some of these events people get stocks with
adjustable LOP but I was really hoping to stock with a standard
looking "old-fashioned stock" for NYC legal reasons.


Any insight to why I am having issues and others are not, would be
appreciated.

[Rich@CCC]

Deleted to wait for someone with more knowledge/experience to ask the right questions.

[StraitR]

Do you have a large variation in shooting positions that prevent you from putting your cheek down at the same stock location when changing positions? If you get straight behind your rifle in the prone, rifle in-line with spine, but then blade your body when kneeling or standing, that difference will likely prevent you from putting your face down at the same stock location without increasing LOP or shifting the optic forward.

I'm not suggesting the ability to change LOP on the fly as a solution, but rather consider your shooting positions and find some sort of balance between them.

Another suggestion is to find optics with more forgiving eye boxes. Higher magnification, larger variability (e.g. 1-8x/3-15x), and inexpensive "budget" models are common factors in eye box/exit pupil size.

[TAZ]

Not sure about the Bushnell, but I'm not surprised that the PA has limited eyebox. It's one of those things that drop off as the cost drops off. I have a 1-6 ACSS Gen2 on an AR that I had to find a happy median mounting location on. I have to slightly adjust a bit when I switch between prone and offhand, but if you're having to move inches you're going to need a giraffe neck to compensate. Have the same issue with cranking the power level up on the PA. No such issues with the IOR on my 18" AR.

Have you contacted either manufacturer to see what they suggest? I know PA was pretty helpful when I had questions. May be worth an email.

[Gray222]

It is very weird that you would have to move the optics from one position to another due to position. That is not standard.

The position of the optic should be figured out in this order:

1. Make sure you install the optic into the mount properly and securely (follow manufacturer instructions and specs)
2. Set the optic on maximum magnification
3. Shoulder the rifle in your preferred position, if you will be shooting prone with this rifle more often than other positions, then shoulder the rifle in a prone position.
4. Loosely mount the optic onto the rail until you do not see any scope shadow/vignette - that means you should start out a little further than you would believe and work your way towards your eye until there is no scope shadow/vignette visible.
5. Set the optic to lowest magnification and make sure there is no scope shadow/vignette.
6. Install the optic onto the rail following all install specs/instructions/etc.

This should work for either eye and any position.

[Clusterfrack]

In addition to VDMs excellent advice, I recommend building a cheek rest for your guns using pipe insulation foam and tape. Without a consistent cheekweld, you're going to be fighting an uphill battle--especially prone.

The best way to do this is to unload, take out your bolt, insert a chamber flag, and have someone look into the front of your scope while you are behind it. Your proper cheekweld is when they see that your eye is centered.

Plus, your homebrew cheekpiece will make you the coolest kid on the block.

[nycnoob]

Cluster,

I have a cheek piece, I use the matthewsfabrication.com http://matthewsfabrication.com/product/adjustable-kydex-cheek-rest/ on both rifles.
but this is because I have the scope on the Bobro QD mount on the scope so I can move it around.


VDM,

I just rechecked the Tikka, I can not find a place to put the scope so that there is no scope shadow in both positions.
When I am prone I want to move the scope about 4/5 rails forward to get a good view. I have left the settings
in one position (either min/max power) and adjusted prone then stood up and it was like looking down a tunnel.
I know that some highpower shooters move their LOP about 2 inches so this appears to be typical. When we first
installed the cheek rest, we did not read the instructions which were to adjust the rest from prone. so we had to
drill extra holes in the 10/22 stock because the prone cheek weld is far infront of the offhand cheek weld.


I do not have a preferred position. For both rifles I use them in "competition setting" where I will shoot
1 string offhand, 1 string sitting, and then 1 string prone, then put the rifle away.

[Gray222]

I would figure out a position to put it where there is no scope shadow probe and then deal with it in other positions, as there seems to be limitations.

Remember the optic does not have to be centered in the mount. It can be a little forward or back as long as the turret posts don't touch the mount rings.

Firing position
Head position
Optic position
Optic position in mount

In that order, yes it means you may need to mess around a bit.

This is much easier on an AR platform rifle or an optic/mount combo which has a lot of room to work with.

[nycnoob]

I would figure out a position to put it where there is no scope shadow probe and then deal with it in other positions, as there seems to be limitations.


I do not understand you last comment. Perhaps some photos will help.
I have been using the rifle in this configuration for a year or so including classes with Randy Cain and some HighPower matches.

[Clusterfrack]

Probably the best way to solve this is with expert help in person. Alignment on magnified optics is fairly precise, even with expensive scopes, and there are 6 degrees of freedom to work with. Let's start with when it's working well. When you're aligned (no shadow), how close are you to the edges of your eyebox? Are you symmetrical? Are you looking out of the center of your eye? Is your head in an awkward position? Someone looking in from the front of your TOTALLY SAFE rifle can help with this. Once you have one good position, figure out how to approach this in other positions.

It may be that your setup isn't going to work. I've had some people show up with scopes so low, they had to tilt and twist their head.

I'm guessing the folks at Appleseed can get you squared away.

[Gray222]

Have you tried scope rings?

The issue may be the mount size. It's not really made for that rifle.

[okie john]

Have you tried scope rings?

The issue may be the mount size. It's not really made for that rifle.

This. You're not doing yourself any favors with that scope up so high.


Okie John

[nycnoob]

Have you tried scope rings?

The issue may be the mount size. It's not really made for that rifle.

I used the regular rings at first. I could not find a position which worked for both standing and prone so I went to a more "flexible" solution.

Yes the mount is high, that is why I put an adjustable cheek rest on the stock to get my eye in line with the scope.

I wonder if the issue is the eyebox on the scope, where ever I place it, I need to move the scope for a different position.

[StraitR]

Can you mount the stock, placing your cheek in the same position each time, no matter what shooting position you're in? If you cannot, that is your issue. It's basically what I said in my original post.

[nycnoob]

Thanks for your help. I am not understanding the advice given here so I will go with plan two.
I am going to see several instructors over the next few weeks, who are also know for rifle instruction.
I will bring my rifle along to the classes and see if I can get some non class time to help with
with this and perhaps they can explain it / demo it in a way I can understand the advice.

[okie john]

That should get you on the right track.

Just in case, take a scope in conventional rings and any tools that you'll need to change between the two.

Then get back to us and let us know what they said.


Okie John

[nycnoob]

Just in case, take a scope in conventional rings and any tools that you'll need to change between the two.



Regular scope rings just will not work. The large bell near the eye piece will not allow rings to be mounted at that point,
so the rings and the base have to be offset. I had to put a rail on the rifle for this reason alone. I may not need all the
length of rail that I have because of the offset base on the rings but it was not clear when ordering how much of each I would need.

[nycnoob]

That should get you on the right track.

Just in case, take a scope in conventional rings and any tools that you'll need to change between the two.

Then get back to us and let us know what they said.


Okie John



I have not been to the range much on my own this past year, so sorry
for the delay in responses. I even joined a 300 yard range this April
but have never shot there!

But I have taken the Tikka rifle around to numerous classes and tried
to get answers.

I give the answers here just in case they may help others with similar
issues. I spoke with several instructors and this is the summary of
what they said (approximate quotes).


John Murphy: I understand what you are saying, but this is not my
wheel house, so I will stay in my lane and not give you a potentially
incorrect answer.


John Farnam: Everyone has issues with getting rifles to fit and work
with accessories. So if you have something which works for you, no
matter how ugly, you are ahead of the game.


Applied Ballistics Seminar, the gunsmith to Bryan Litz. We looked at
the rifle at night, in a parking lot, with plenty of overhead street
lighting, we were not able to go prone and they seem to mostly (only?)
shoot prone my issue is with multiple positions: I would not worry
about the scope being mounted so high, we mount ours even higher and
then just dial the elevation we need. Your eye box seems adequate, so
work on adjusting your position to fit your scope.



Kyle Lamb (2 different rifle classes):
First class he commented "Boy that eye box sure is not very generous"

Second class I brought a 10/22 with a Primary Arms adjustable scope
mounted on it and the class lent me a Lupold scope and I brought my
Tikka with the scope mounted as above to compare. Really I think the
Primary Arms scope is noticeably better than the Bushnell.

This class was at the Southern Exposure range where I took the Randy
Cain classes, however this time I was able to see some interesting
chromatic aberations in the Bushnell scope that I never noticed
before. When the sun came directly from behind and reflected off the
target, right where the black part of the target met the white part, I
could see patches of dark purple (and orange). It made it hard to aim
at say a 6 o'clock hold during those times of the day. Neither the
Lupold nor my Primary Arms scope showed such issues.

Kyle's only issue with the scope mounted "so high" (really same height
as optics off a AR barrel) was if I was going to have the first zero
real close (like 25 yards) he recommended more of a 75-100 yard zero.
If you look at a ballistic chart of a high mounted scope you can see
that between the two zero distances the bullet travels really high
above the line of sight. He was concerned that in a military situation
you might misjudge the distance to your target and when you shoot to
point of aim you could have the bullet pass over your target. By
moving the first intercept further out you will lower the maximum
height of the bullet over the target and increase the chance of
hitting. This is a restating of Bryan Litz's "Danger space" concept. I
am planning on only shooting at point blank range (100-300 yards) at
known distance targets so I am not concerned about this.

Obviously the Lupold scope was a much better scope than either of my
two scopes. The eye box was more generous and the scope was noticeably
clearer. I just ordered a 3-15 Lupold scope with a 1/2 price coupon
that I got from the class. I will continue to use the rail and the
Bobro quick release offset mount. I find it very handy to be able to
switch my optics between rifles using the quick release feature.

Also I had a chance to examine lots of different spotting scopes (at
the 100 and 200 yard line). I think most of what was on the line was
expensive but no clearer than my 80$ unit. The few that were actually
outstanding were discontinued models and obscure brands. Since I do
not expect to shoot more than 300 yard targets, I think I will skip
the spotting scope and go with the target vision camera.
https://targetvisioncam.com/collections/spotting-scope I will wait
till spring to purchase this because their may be upgrades announced
at SHOT or NRA.

I had planned on shooting both the Kyle Lamb courses with my gas gun.
However the first course my gun had issues so I had my kitchen table
gunsmith give it a good once over and steam cleaning. I tested it
briefly and it seem to work. For the second class that gun locked up
real tight during the first course of fire. I had to use the Tikka
for the whole class, after the class was over I sent the gas gun back
to the manufacturer for their opinion on my problems.

The Manufacturer said it looked like I had lacquer in the action.
They had never seen that issue before and could not advise me as to
the cause of my problem. I believe that the issue was in my effort to
prevent any problems for this second Kyle Lamb class I lubed the bolt
just before class with "Breakfree CLP". In retrospect, I remember
reading that Pat Rogers had a similar issue with that product. So my
guess is that I should not have used that as lubrication.

However I have owned this rifle for over 5 years and used it at many
classes. So I am not sure what lube I was using before. I use
"Breakfree CLP" for most of my cleaning, so I must have been using
another lube for the rifle in the past and this time slipped and used
CLP as the primary lube and had it bind up the action.

[Lomshek]

Perhaps some photos will help.
https://pistol-forum.com/attachment.php?attachmentid=17333&stc=1&d=1497456726

I have been using the rifle in this configuration for a year or so including classes with Randy Cain and some HighPower matches.

I'm an Appleseed shoot boss and have dealt with this for myself and others. Most scope mounting solutions are designed to place the scope comfortably for bench shooting with the head essentially vertical.

Positional shooting is much better with the neck extended (comfortably) forward which correspondingly moves the head forward and down. That requires moving the scope forward usually a few inches more than any traditional scope mount will accommodate. Most stocks likewise are too low for most scope mounting solutions so you end up using a jaw weld or chin weld instead of a more solid and repeatable cheek weld.

All of that contributes to a much more difficult time shooting a scope accurately in anything besides bench or bipod shooting. Most folks never learn a better way and just assume that's the way it is and scrunch their head and neck to sort of see through the scope.

Here's what you need to do.

First get the lowest rings that will allow the scope to be mounted to the rail. To figure that out just measure the largest diameter of the eyepiece in inches, divide it in two and round up to the nearest height scope ring height made. A 40mm eye piece is 20mm from center to bottom. 1" is 25.4mm so get 1" rings.

Next mount the rings in the two forwardmost picattiny slots of your mount they'll fit in with each ring pushed forward in its slot (there will probably be an unused slot between them). Place the scope in the rings with both rings behind the turret but the scope slid as far forward as possible in the rings. Gently snug the bolts down but don't bother tightening them, you'll be adjusting them soon. That will have your scope eye piece as low as it can go and as far forward as physically possible for your starting point.

Check out this photo of a scope mounted as low and forward as possible on my DDM4V7 using the same mounting situation.
31760

31762

Here's a 10/22 I set up for a friend for Appleseed using a cantilevered rail.
31761
The 10/22 stock is short for his 6' tall frame so he's more squared up which means the scope is moved back a tiny bit. An adult size stock would require him to angle more off the side of the rifle which would move his head forward and require the scope to go even further forward.

Go prone and shoulder the rifle. Figure out your optimal body angle relative to the rifle (straight behind would be 0 degrees and turned completely beside the rifle would be 90 degrees). The ideal body position is whatever gives you a stable position with the butt solidly in contact with your shoulder. Appleseed and old school marksmanship teaches a 30 degree angle off the rifle as ideal but in reality everyone fits their rifle different and has to figure their ideal angle out. It may be more like 15 degrees (more squared up behind the rifle) if the stock's LOP is a little short for you or closer to 30 if it's as long as you can use.

On AR's I'm all about an aggressive NTCH head placement and adjusting stock length and body angle to make that work optimally. For other rifles it's really just finding where your head lands with your neck comfortably extended forward and figuring out what needs changed on the stock to make that work. If you use a cheekpiece it'll need to be further forward than most are designed for.

Once you have your body angle figured out look through the scope and decide how far back you need to move. At first just use the picatinny slots to move back one slot at a time and once you get close to the right eye relief start sliding the scope forward and back in the rings. Eventually you'll settle on the correct eye piece location for ideal eye relief while your head is in a forward position.

Finally decide how high of a cheek piece you need (for non-AR's) so that your cheekbone in laying solidly on the stock instead your jaw laying on the stock.

For AR's the 1" rings worked perfectly for me but I'm now messing with a Geissele national match mount with 3" of forward cantilever so I don't have the hokey ring mount. The G mount is 1.3" high instead of 1" but I'm going to get a Magpul UBR which will raise my cheek at least .1" and get me close to a solid cheek weld.

I suspect that you'll end up needing an extended rail that gives you 2"-3" more rail in front to mount the scope far enough forward and properly locate the rings with one on either side of the turret. Once you get the scope placement optimized for you you'll know.

You're going to struggle to find people to help you with this because most folks don't do that kind of shooting and even among experienced precision shooters they tend to set the rifle up for modern bipod shooting squared up behind the rifle which is totally different. Even among Appleseed shoot bosses most of my compatriots have not explored it enough to figure out how to truly optimize the shooter and rifle for scoped shooting.

A few truly skilled High Power shooters probably know how this works because they are in pursuit of excellence so if you have a good club around you might find one of those guys who can help.

Last photo.

This is the level of accuracy I'm able to attain with the goofy 1" rings mounted behind the turret of my scope on my AR and a very solid cheek weld.
31763

The groups were fired at 685 yards prone and slung up like Appleseed teaches. The rifle is a DDM4V7LW with a Burris 1-4X MTAC using single fed 80gr SMK's. The top right 3 round group is about 4 1/2". The center group is 8" if you count the high right round I called as a jerked shot and 5 1/2" for the 4 rounds that I called as good shots.

When a rifle really fits you it's incredible how stable you feel behind it. Hope all this helps.

Edited to add - The one piece mount you have looks cantilevered forward enough to mount the scope properly for good eye relief on an AR but like most is high enough to match iron sight height (1.5 or 1.6" high). That's way too high for the additional head stability that a scope's eyebox demands for good shooting. PRI makes a 1.3" high cantilevered mount that would work for about $100 as does Geissele for more. The Geissele costs 3.5X more than the PRI but the G mount is a lot stronger.

People don't think that matters until they shoot a properly positioned scope and suddenly the light comes on as they get behind it!