Rifle Scopes Is it possible to have too little clearance?

[Deo]

Hey guys, I know you should always strive to have the least amount of a gap between objective bell and barrel as possible, but is there a point where that gap becomes too tight? I'm trying to figure out if I should go with Nightforce low or medium rings right now, and based on my calculations I'd have .97mm gap with the lows and a 3.89mm gap with the meds. This does account for BC caps that I plan to put on the scope in the future.

My math is [rail height + ring height] - [bell diameter x 0.5]. So
[8mm + 22.48mm (lows)] - [57mm x .5 = 1.98mm - 1.01mm] = .97mm for the lows, or
[8mm + 25.40mm (meds)] - [57mm x .5 = 4.9mm - 1.01mm] = 3.89mm for the meds.

Now I don't have an exact measurement of the rail height from the barrel, but from what I've read on SH it's around 8mm.

Also, i'm using a 20 MOA NF 1 piece base. and a WOTAC 4x14x50 on a rem 5R.

So my question is, are the lows too low? Should I go with the meds? Thing is the meds seem a bit high to me, and the lows a bit low, what do you guys think?
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[Straight Shooter]

Re: Is it possible to have too little clearance?

As long as you can get your head low enough for proper cheek weld and a good centered look through the scope I like them as low as possible. As long as the scope is not touching the barrel there is no such thing as too low. The higher the scope is the greater the error from canting.

 

[TrooperBrian]

Re: Is it possible to have too little clearance?

I'd say the lows are way too short. Leave at least 1/8" in there, during recoil its unlikely that they will make contact, but if you watch highspeed video of a rifle shot, the scope and barrel actually "flop" a significant amount. Thus why freefloat is so important.

Your scope does it too, its ATTACHED to the action!

 

[Deo]

Re: Is it possible to have too little clearance?

Then I guess the meds are what I'll go with, thanks guys

One more question, is there any way to tell if the bolt will clear the eye piece? or is that just something I wont find out till I mount the scope?

 

[TrooperBrian]

Re: Is it possible to have too little clearance?

Clear the eyepiece? Your bolt shouldn't need to rotate enough to pass the path of the scope.

 

[Deo]

Re: Is it possible to have too little clearance?

Oh, Thanks Brian. This is my first real precision bolt gun you see, and I heard someone warn me about rings being too low and causing problems with the bolt and eye piece.

 

[19Scout77]

Re: Is it possible to have too little clearance?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TrooperBrian</div><div class="ubbcode-body">I'd say the lows are way too short. Leave at least 1/8" in there, during recoil its unlikely that they will make contact, but if you watch highspeed video of a rifle shot, the scope and barrel actually "flop" a significant amount. Thus why freefloat is so important.

Your scope does it too, its ATTACHED to the action! </div></div>

OP- Remember that you get what you pay for when it comes to internet advice--particularly when based upon youtube videos and not actual knowledge and experience.

 

[lane223]

Re: Is it possible to have too little clearance?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TrooperBrian</div><div class="ubbcode-body">Clear the eyepiece? Your bolt shouldn't need to rotate enough to pass the path of the scope. </div></div>

My experience differs. I have a CZ 527. I first tried some Millet 16mm dovetail rings I had laying around to mount a Falcon 4x14x44mm scope. No go. The bolt handle hit the zoom ring. I then used a 16mm to picatinny adapter base and Warne low rings. Worked great with about 1/4" clearance. With the Remmy 700 I never had problems.

 

[Deo]

Re: Is it possible to have too little clearance?

The thing is I have to order my rings from the US, and me being in Canada I don't want to have to ship them back and pay for shipping and duty again if I get something thats the wrong size.

If my math is correct, am I right in the sense that the lows are too low? I'm sure the barrel would make contact with the scope as soon as I put the sunshade on because it is a canted base. Would I be better off with the meds? Or am I missing something in my math and what not?

 

[Hellbender]

Re: Is it possible to have too little clearance?

Mock it up with some cardboard shims under your scope and tape the scope in place, then measure. Check for bolt handle clearance.

I worry more about getting proper eye relationship and cheek weld than getting the scope as low as possible.

1/4" or even 1/2" higher won't make a whit of difference in your ballistics, BUT will make a huge difference in how your eye centers behind the scope and how consistent your cheek weld is.

Close your eyes and get very comfortable behind the gun, then when you open your eyes THAT'S where your scope needs to be, however it falls in relationship to the barrel doesn't matter.

 

[ewoaf]

Re: Is it possible to have too little clearance?

something else to think about is whether or not you're going to have a BC cap on there. You may want to spin off the sunshade for cleaning w/o having to take off/on caps and what not.

 

[Deo]

Re: Is it possible to have too little clearance?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ewoaf</div><div class="ubbcode-body">something else to think about is whether or not you're going to have a BC cap on there. You may want to spin off the sunshade for cleaning w/o having to take off/on caps and what not. </div></div>

Yes I do plan to use BC caps.

 

[TrooperBrian]

Re: Is it possible to have too little clearance?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 19Scout77</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TrooperBrian</div><div class="ubbcode-body">I'd say the lows are way too short. Leave at least 1/8" in there, during recoil its unlikely that they will make contact, but if you watch highspeed video of a rifle shot, the scope and barrel actually "flop" a significant amount. Thus why freefloat is so important.

Your scope does it too, its ATTACHED to the action! </div></div>

OP- Remember that you get what you pay for when it comes to internet advice--particularly when based upon youtube videos and not actual knowledge and experience.




</div></div>

If you want to throw the experience card, I've seen it happen in person. With a scope too close to the barrel and magnum calibers, a significant bit of scuffing begins to appear under the scope where it runs close to the barrel.

So before you accuse someone of talking out of their ass, perhaps a video is worth 10000000 words.

 

[Straight Shooter]

Re: Is it possible to have too little clearance?

How big of magnum are you talking about? I can get one sheet of paper under the scope bell on my 7 Mag and when I changed out that 25 year old scope it didn't have any signs of touching and that rifle was run hard. I run my VX-3 8.5-25x50 with a scope shade about .050" over the bore on my 300 Weatherby using Leupold double dovetail bases and Burris Signature rings and that scope has never touched.

The only video I ever saw on youtube showing a bunch of flex was 50 BMG stuff.

 

[Deo]

Re: Is it possible to have too little clearance?

I'm running this on a .308, so I guess I don't even need to worry about the bolt touching. Do you think there would be any flex with the .308? Or will those lows work just fine?

I sent off an email to Nightforce to see what they say. I figure it's best to get a couple different opinions, especially one from the company who makes the products i'll be using.

 

[VKC]

Re: Is it possible to have too little clearance?

I would go with medium height rings as well for a little more clearance. If you want to get a better idea of measurements, suggest doing tracings on cardboard. Trace out you rifle and stock, and then scope. Measure from your eye down to bottom of cheekbone where you "sit" your face to the stock. Check the height from the middle of your scope objective to the top of the butt stock, and compare to eye-cheekbone measurement. If this distance is a little different, then you can probably get by using a stock bag with padded cheek rest. If this distance is large, then you will do better with raised cheek piece. Also with working the bolt action, you want to make sure that you have enough room so that you hand does not hit the rear of the scope with cap open.

You can also check the scope eye relief distance and see if the distance fits with where your face will be positioned on the stock. I placed a Karsten cheek piece on my rifle and marked the spot where I will get ideal eye relief on the cheek piece.

Your bolt should be able to clear the rear of the scope with lens cap when stripping, and also the front of the cheek piece. Remember the you may need to rotate your bolt to remove or reinstall.