Scope height, cheek weld and eye relief

MFGRVA

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May 19, 2020
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Central VA
Hi all. Longish lurker, new member.

I've been a hunter for some 38 years now, have competed in service rifle matches in the past and generally consider myself a competent marksman. That said, I'm just now getting up and running on what I would consider to be my first dedicated long-range rifle, a 700 5R Gen 2 in 6.5CM. I'm initially set up with a Seekins 20MOA rail/low rings and a 3-15x44 Viper PST.

At the risk of sounding ridiculous (I tend to analyze the hell out of things, lol), I wanted to ask for opinions on scope height versus eye relief... with the combination that I initially chose, the scope height is just about perfect for my natural position/cheek weld, however I am unable to get the scope quite far enough forward for the eye relief to work with that natural position - the eyepiece simply cannot slide forward past the end of the rail. I've attached a photo of the clearance issue I'm running into.

The opinion that I'm interested in hearing is whether it would be better for me to relearn my position to deal with it, to alter my position on the stock via the use of a slip-on recoil pad (altering LOP) and leave the glass as-is, or do I raise the scope to allow the proper eye relief and install a cheek riser?

My preference would be to keep the scope as close to the bore center as I can, but there is something about having the eyepiece that close to a contact point on a rifle that's going to see field use that makes me a touch nervous for some reason.

What would you do?
20200602_171901.jpg
 
Agree. I suppose what I meant was that if I close my eyes and shoulder the rifle currently, I'm naturally in line with the scope when I open my eyes, just a bit too close and I need to move my head back a touch to get the proper eye relief. If I raise the scope, say, 5mm, so that I am able to move it forward on the base, would I not then have to alter my cheek weld on the stock in order to remain in line with the scope? (In other words, raise my cheek's position on the comb)

I fully understand that were taking very small distances. Maybe so small that the additional height wouldn't really matter?
 
Agree. I suppose what I meant was that if I close my eyes and shoulder the rifle currently, I'm naturally in line with the scope when I open my eyes, just a bit too close and I need to move my head back a touch to get the proper eye relief. If I raise the scope, say, 5mm, so that I am able to move it forward on the base, would I not then have to alter my cheek weld on the stock in order to remain in line with the scope? (In other words, raise my cheek's position on the comb)

I fully understand that were taking very small distances. Maybe so small that the additional height wouldn't really matter?
Yes, you are correct. Higher scope clearance would change your cheek weld. The other option is to increase the length of pull - you can do that with an after market spacer or recoil pad, or new stock.
 
How much are we talking? Could you modify the mounting rail by cutting it off flush with the back of your rear ring or grinding away material from it to provide clearance? I'm smaller in stature so adding length for me is less preferable than increasing scope height, especially when hunting in colder temps and wearing bulky layers.
 
About an inch, more or less. I've added a Pachmayr slip-on pad to the mix to get a bit more length and it does seem much better handling it around the workshop... I'll be taking it out this weekend and am hoping that I'll be able to call good.

If it does work well, perhaps at some point I'll pay to have spacers added to the butt on a more permanent basis (spacing out the HS Precision stock is more than I really want to tackle at home).
 
Honestly I wouldn't try to mickey mouse a solution, like putting an improper length of pull, or settling on improper eye relief, or making it too high, that is, if the length of pull is correct as is. Having excessive LOP isn't optimum, especially for prone shooting. Get rid of the rail, and get a something like talley/dnz/nightforce ring/base combo's that can get you to the right height you want and allow you to move the scope forward to where it should be and maintain the correct LOP.

Having to compensate for something not being natural is going to hinder your ability. Might as well just do it right from the start
 
I agree about mickey-mousing it, which was the intent of asking for opinions on the adaptations to consider (LOP, scope height, position).

The height of the scope is spot-on as it sits. Eye reflief removed as an issue, the LOP isn't really a problem as-is but it is certainly not in danger of being too long. At just a shade under 6'2", "too much" LOP hasn't really been a thing that I've had to deal with.

My concern with going with higher rings to enable more eye relief is/was that by raising the scope that I would then need to raise the comb. I could also modify the rail pretty easily to allow the scope to move more forward, but given that LOP is the easiest thing for me to change I'm going to try that first and see how it works, despite my general dislike of slip-on pads.

I appreciate the responses so far, if there's something else I'm overlooking please keep them coming.
 
If you close your eyes, shoulder and open and your height is spot on, do not change the LOP. Change the position of the scope.
What's your scope magnification set at? At high magnification, eye relief will shorten by as much as 8mm. If you look at the Viper PST specs, the eye relief is listed at 3.14", but they don't list high/low. That's pretty close, IMO.
Some thoughts:
  • Is it the Seekins 20MOA rail that prevents you from moving the scope forward?
  • The internal adjustment on the PST is listed as 75moa. Essentially 38 up / 38 down. Have you spec'd bullets with trajectories that will get you to 1000 with that adjustment?
  • Do you plan on shooting farther?
Without modifying the ergonomics of the rifle (changing LOP), the cheapest option would be swap out the rail. Second option, if you have the funds, would be to try a different scope. If it works, sell the PST. You may be different, but I've tried foam cheek rests and they don't work for me, i.e. I have never found a repeatable position. I hate adjusting my head when I pull up. I also hate having to raise my head for proper sight acquisition.
 
Agree. I suppose what I meant was that if I close my eyes and shoulder the rifle currently, I'm naturally in line with the scope when I open my eyes, just a bit too close and I need to move my head back a touch to get the proper eye relief. If I raise the scope, say, 5mm, so that I am able to move it forward on the base, would I not then have to alter my cheek weld on the stock in order to remain in line with the scope? (In other words, raise my cheek's position on the comb)

I fully understand that were taking very small distances. Maybe so small that the additional height wouldn't really matter?

Since you asked what everyone would do, I will tell you that I would go to the slightly higher ring. But yes, it will change your head position. You will have much less of a cheek "weld," perhaps just a light touch in line with your upper teeth, but you might (eventually) find you like it. I certainly did, and still do, because it is much more comfortable when I am scanning for varmints for hours at a time, and the added comfort makes me more accurate, not less.
 
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