Advanced Marksmanship Cheek weld problem throwing groups up and down

[sst04]

I have been having a little problem ever since I mounted a different scope.

Shooting groups is not a problem, however shooting a group in the same place everytime is not happening.

One group will be dead on, then if I get up to switch targets my next group will be over an inch high or a inch low.

The scope is not as low as I would like, it can come down about a quarter inch, The scope I had before was right on the barrel.

I just cant seem to get the same cheek weld everytime. But would this throw the groups off that bad everytime?

I have moved the cheek rest up and down trying to find the right spot, I thought I had it today but after shooting a couple of groups some were high and some were low.

Everything is tight, A box test has been done on the scope and it was dead on. I am thinking that I just need to get some lower rings but wanted to see if you guys had any other ideas. The rings now are 1.12, I have .315 clearence from scope to barrel so a set of 1.00 or the .885 should work.

 

[Redmanss]

Re: Cheek weld problem throwing groups up and down

You've got me stumped a bit on this one. You have an adjustable cheek rest so you should be able to position your head to where your eye is sighting directly through the center of the scope.

How is the higher position of the scope effecting the rest of your position? Is it causing you to have neck strain? Are you positioning the butt stock differently in your shoulder now? Are you witnessing parallax or scope shadow? Is your position identical group to group, but still having the shifts? Did you properly set your eye relief when you installed the new scope?

Any one of these can effect your shot placement. What scope did you have before, and what do you have now, and what height was your previous mounts?

Your fix may be to get you back down to the level you were previously used to, but the fix may also be tweeking your position through dry fire and snapping in. A little more info on your setup would be helpful too.

 

[sst04]

Re: Cheek weld problem throwing groups up and down

The scope I had before was a bushnell elite 5x15x40, now I have a Nightforce 5-22x56. I adjusted the paralex at 100 and marked it on the nightforce. I have moved the scope a couple of times trying to get the comfortable spot to where I am not straining and have a good sight picture.Maybe Im doing it wrong.

To set the eye relief, I went outside and got down like I was going to shoot, closed my eyes and placed my head on the stock and adjusted the cheekpiece until I was looking through the center of the scope. Then I moved the scope foward and back until I got the sight picture with no shadows.

With the parallex adjusted properly, would it really matter if I was a little off from time to time with position?

 

[Sterling Shooter]

Re: Cheek weld problem throwing groups up and down

Remember, when the comb goes up, the butt will need to come up too. Thing is, you can't do that if you don't have an adjustable butt. Without the adjustable butt, consistent butt-to-shoulder placement is more difficult to recognize. My thought is your groups are in a different place because your butt-to-shoulder placement is different between groups.

 

[sst04]

Re: Cheek weld problem throwing groups up and down

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DFOOSKING</div><div class="ubbcode-body">What are you using for a cheekrest? McMillian? Manners? HS? Aftermarket doodad?

My HS precision "M24" and "FBI Sharpshooter" stocks use HS's adjustable riser system which has a thumbwheel on the heel of the stock. There has been numerous times I've caught myself, my bag, my terrain turning the wheel and F'ing up my setup slightly. I can see why the ARMY doesn't use the versions with risers and just going the tape/foam route... </div></div>


The gun is a savage 10, the cheekrest is one I made out of a piece of plastic molded around a piece of round and attached by two bolts. It is adjustable up and down, and locks in place tight.

 

[sst04]

Re: Cheek weld problem throwing groups up and down

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">Remember, when the comb goes up, the butt will need to come up too. Thing is, you can't do that if you don't have an adjustable butt. Without the adjustable butt, consistent butt-to-shoulder placement is more difficult to recognize. My thought is your groups are in a different place because your butt-to-shoulder placement is different between groups. </div></div>


Im thinking you could be right, the butt of the stock does seem a bit low on my sholder. It is the savage tupperware that has been modified to make it stiffer.
I like the gun to be low to the ground, maybe on the second notch on the harris 6-9, If I let it all the way up, its a little more comfortable but I seem to wobble more.

 

[Sterling Shooter]

Re: Cheek weld problem throwing groups up and down

Do not bring your head to the stock, bring the stock to the head, and then shoulder it. You already have one problem, you don't need to compound it with another.

Now, I'm not certain I'm right about you not having butt-to-shoulder consistency; but, one thing is for sure, your error is about some inconsistency, in one or more aspects regarding the position. There are 5 factors which describe the relationship between shooter, gun, and ground. These are: elbows, non-firing hand, grip, butt-to-shoulder, and stock-weld. Make sure these relationships are consistent from shot to shot. Practice will develop motor memory to eventually allow for perfection. For right now, muscular relaxation will give you a feel for when things are right. Holding a rifle BTW with any support coming from muscle is like holding the rifle with Jello, it precludes any sort of consistency. Also, when shouldering the rifle do it without any consideration for the target. This will help prevent steering to target with the non-firing hand while building the position, which could hinder adjustment of NPA.

To get a proper prone height, build a position from bone alone with the non-firing hand on the hand-guard and elbow as close to under the hand-guard as comfortable. Then adjust the bi-pod initially for support at the height established by the elbow support.

 

[sst04]

Re: Cheek weld problem throwing groups up and down

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sterling Shooter</div><div class="ubbcode-body">Do not bring your head to the stock, bring the stock to the head, and then shoulder it. You already have one problem, you don't need to compound it with another.

Now, I'm not certain I'm right about you not having butt-to-shoulder consistency; but, one thing is for sure, your error is about some inconsistency, in one or more aspects regarding the position. There are 5 factors which describe the relationship between shooter, gun, and ground. These are: elbows, non-firing hand, grip, butt-to-shoulder, and stock-weld. Make sure these relationships are consistent from shot to shot. Practice will develop motor memory to eventually allow for perfection. For right now, muscular relaxation will give you a feel for when things are right. Holding a rifle BTW with any support coming from muscle is like holding the rifle with Jello, it precludes any sort of consistency. Also, when shouldering the rifle do it without any consideration for the target. This will help prevent steering to target with the non-firing hand while building the position, which could hinder adjustment of NPA.

To get a proper prone height, build a position from bone alone with the non-firing hand on the hand-guard and elbow as close to under the hand-guard as comfortable. Then adjust the bi-pod initially for support at the height established by the elbow support. </div></div>



Thank you for the info sir, I will try these things this weekend.

 

[inthewind]

Outstanding information! I have seen the foam and tape thing done for cheek weld. How does one build a proper foam/tape on the stock?

I am guessing you start with where your facial bones lay against the stock and build up around that to support soft tissue. You might find the spot with some chalk dust on the stock.

 

[EXTREMEPREJUDICE]

but wanted to see if you guys had any other ideas

parallax problem...............

 

[Sterling Shooter]

Here's the list of things which can cause vertical dispersion:

1. A vary low position
2. Varying rifle butt position in shoulder
3. Poor follow through
4. Changing sight alignment
5. Changing sight picture
6. Not enough head pressure
7. Position of left elbow wrong
8. Changing distance of eye to sight
9. Failure to maintain proper sight alignment

Your problem is likely to be found on this list. I'd suspect muscle memory is compelling you to build your position from what was rather than what is now.

Dry fire from prone with bone alone. This will unmask muscular tension which can be addressed with adjustment of NPA from a properly built prone position. From there, you will be able to concentrate on making the relationships or contact between shooter, gun, and ground consistent, building new motor memory. The bottom-line is right now you have inconsistency which cannot be discerned or felt. Building the position without artificial support will reveal these inconsistencies.

You could also see vertical groupings from ammunition which has as an extreme spread in the 50 fps arena; but, shooting tested ammunition will eliminate the concern for inconsistent velocity, as well as the inconsistent recoil resistance it promotes.