Phisiological issues while shooting prone?

According to the guys I know who shoot a lot and are instructors, shooting prone causes stress on the muscles of your neck and also can slow the flow of blood to your brain. The blood flow part is especially important, as it will effect your eyes. When I started my rifle training, I was told that if you stay prone for too long, you could even pass out.

Getting off the scope and lowering your head should help. This will help prevent eye strain, too.

I usually get up and walk around for a bit every ten to fifteen minutes or so, which is not a problem at my range, cause everybody wants to chat! If I take 100 rounds, I'm lucky to fire 50 if anyone else is on the range. Maybe this is why my load developement is taking so long?

A chiropractor might be able to help with the postural problems.

Are you stretching prior to shooting?

Reason I ask is, there is a muscle (sternocleidomastoid) runs from the below the ear to your clavicle. That muscle runs over the carotid and when flexed or stretched for long periods will put a little pressure not enough to block it but enough reduce blood flow to the brain. This is where the headache and eye pain may comes from. A solution for the long term would be stretching the muscle and strengthen​ it. Doing some Supermans every morning and stretching for 10 minutes in the morning could make a huge difference. It should increase the range of your natural point of aim.

Good suggestion, but I gotta ask, what's a "Superman"? I'm fairly certain that a "Clark Kent" is just about all I can handle. :-D

When I was in boot, they called it "Shark". Lay face down on the floor and get into the pose like Superman when he's flying. Keep your legs and arms off the floor. For additional effect, move your legs and arms up and down a couple inches almost like you are swimming. Do this until you can't hold your arms and legs up any more. Relax a minute or two, then do it again. Repeat until your core feels like jelly. In addition to your core, your neck and shoulder muscles will get quite the workout as well, which in this case, is the entire point.

I too used to experience headaches on occasion when shooting. In my case I believe it was tied to recoil, not the prone position itself. When shooting rimfire matches, I could be shooting a Winchester 52D for up to 30 minutes at a time in the prone position. Longer during practice sessions. Never had a problem. When shooting centerfire rifle prone or clays with a 12 gauge I would get a headache after 20 rounds prone with a rifle (usually a .30-06 or similar, sometimes larger) and after exceeding 50 rounds with the shotgun. None of the rifles I shot back then had brakes. My current rifle has a very effective (and LOUD) brake, as did another rifle I recently sold, and I have had no issues with headaches at all with either of them. Both .30-06.

I do believe the type of recoil impulse has an effect on whether or not I get a headache. A few times I tried shooting a Remington "Mohawk" 12 gauge autoloader for sporting clays. Each time I barely made it through a box of shells before I had a splitting headache. That particular gun was inertia operated, the barrel and bolt moved rearward with the recoil for an inch or so until the barrel hit a stop and the bolt continued rearward. It felt weird in that for every pull of the trigger, you got kicked twice.

Wonder if doing something to alter the recoil impulse would help you? Try using a notched heavy sandbag between the butt of the rifle and your shoulder. Some call them "sissy bags" but they do work. Not exactly practical to carry in the field, but worth a try at the range as a troubleshooting tool in your case.

In his video series "Long Range Made Easy", Todd Hodnett, who has become a very prolific trainer in military circles http://www.recoilweb.com/todd-hodnett-the-long-range-cowboy-108460.html , recommends having your comb height adjusted so that you can lay your head down on the gun like you were going to fall asleep there. When you open your eyes, he says, you should be looking through the center of the reticle.

Perhaps if you concentrate on establishing a very relaxed, restful, "sleeping" position when setting up your comb height, you may find some relief.

Before I adjusted my comb height high enough to accomplish this, I used to be engaging my neck muscles ever so slightly more in order to get my eye position fine tuned behind the scope. After following Todd's advice I notice much less neck strain and headache.

You don't need to relax quite as much between shots if you are already relaxed in your shooting position.

The other thing that comes to mind is diopter adjustment and parallax. I've heard that having your diopter adjusted sub-optimally can lead to "depth of field" focal difference between your target and reticle once you have adjusted parallax to minimize reticle shift on target when your eye moves around the eyebox(which is how you should be adjusting parallax). I've heard that even a relatively small maladjustment here can lead to increased eyestrain and headaches after a time. I guess some people are more susceptible than others.

There are a lot of good tutorial videos and articles on diopter adjustment out there, by people more qualified than me, but here are the high points.

1, Make sure you are doing it with the parallax set to infinity(if so equipped).

2, Use either a blank wall(close) or clear sky(far) with nothing to cause your eye to focus at a particular distance. You need a completely blank background.

3, You can only peek at the reticle for a moment(half second or so), or else your eye will automatically shift focus to make the reticle appear focused, which completely defeats the purpose of diopter adjustment. This is where many people seem to get it wrong. It's like a trip to the eye doctor; they show you two images, briefly, and ask you "which is better". That's how you need to approach this process.

4, Start with the diopter adjustment cranked in all the way to the RIGHT, take a quick look(half a second)and then back it off to the LEFT a ways. Keep repeating this procedure, turing LEFT each time, until the reticle just gets UNFOCUSED and fuzzy.

5, Now start turning the diopter back to the RIGHT using the "which is better" approach until it gets FOCUSED again, remember only look for a moment(half second or so). Use finer adjustments during step 5 as you get closer to optimal reticle focus(diopter adjustment).

6, When you're done, the diopter should be adjusted as far to the LEFT as possible, while the RETICLE IS STILL FOCUSED AS CRISPLY AS POSSIBLE. Remember the diopter is only used to focus the reticle to YOUR eye, then don't touch it again! You will want to do this with whatever glasses or non prescription safety lenses you wear when you actually shoot. Take breaks during this whole process to allow your eyes to rest. Look around, look out at the horizon line, don't be in a hurry. If you get lost, take a break and start over. It may be advisable to mark your final setting when finished, to easily identify and remediate accidental maladjustment.

These are my best guesses, although I claim no particular expertise. I try to only regurgitate information from sources that I feel are well vetted and respected. I think paying particular attention to these two principles while setting up my gear has helped me to minimize the same issues you are having. Sorry for the long winded post if this seems too remedial to you, but perhaps it will help somebody else down the road.

Good luck, and good shooting!

I just saw that I forgot to mention length of pull as it relates to scope eye relief. It's also an important part of the relaxed"sleeping" position. If you are engaging your neck muscles to move your head forward, or perhaps especially turtling backward, in order to facilitate optimal eye relief, it may be as bad as poor comb height adjustment.

Just lay down behind your rifle, shoulder it, then relax like you're going to take a nap. Forget about the scope. RELAX. You're taking a nap. Now open your eyes. If you're not very, very close to centered in the scope's eyebox when you open your eyes, then you're not really relaxed when you're using it.

Thanks for the help guys! I have been out a couple times since, with a little better results. I adjusted the cheek rest and added some more mousepad underneath to raise the comb a bit, and pulled the scope back again. Maybe someday I'll upgrade the stock a bit, add a kydex riser or something since its a straight comb, and I that's causing some issues with having to tilt over to see in the scope.

Also stretched and relaxed while shooting. Its still not 100% but I'm thinking if I can get out more often I will be able to build whatever callouses and muscles that are needed. Additionally, I think I need a scope with more diopter adjustment since it is such a pain to get a clear picture (Right eye astigmatism). I think the Valdadas have quite a bit more in that department.

I'm a Firefighter - Medic . Lots of staying low to the ground, head tilted up while firefighting. During long live fire training evolutions, I'd get the nasty headaches. I've always had neck issues and migraine headaches. Keep in mind that Migraines are related to the vascular system's response to stimuli like adrenaline. Firefighting provides plenty of adrenaline stimulating activity as so does shooting. Anyway, I told my doc about my neck strain and migraines going hand in hand. He said I could be experiencing cervicogenic (of the neck) migraines. He sent me to a pain management doctor. They did a series of injections into my cervical spine (neck)... while knocked out... called "Facet Blocks". Didn't get a single headache for a year! Something to consider.