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High Scope Rail?

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J

Jspool

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Jan 3, 2021
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Port Orchard WA, United States
I’ve always been in the camp to mount my scopes on my rifles as low to the barrel as possible. Now I’m looking at a custom stock for my AA TX200 MKIII and they are all fitted with very high (imo) scope rails.
I did some research on this forum, and Solo1 wrote:

”Your scope height affects at what point the flattest part of your trajectory lands. That’s why you see 12 fpe ft rigs sometimes with very high scopes so they can range more at closer distances and be right on at 55”

My old brain can’t get wrapped around this. I’m sure that if the pros are doing this it must be effective. Can so eone explain this to me. A diagram would be amazing.
Jonathan the Noob
 
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+1 with dizzums

Sorry no picture/diagrams.

Most 12 FPE WFTF shooters will use higher scope mounts so that the hold overs or clicks are minimized at longer distances (40-55 yards).

Here's an article by Scott to find the optimal scope height to shoot FT. "...One of those factors is ranging error. Scope height determines at what distances ranging errors are most detrimental. Targets near your zero are more tolerant of ranging errors."

Optimal scope height study - Airguns & Guns Forum

Optimal scope height study, Air guns, Airgun Forum
www.gatewaytoairguns.org
 
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Basically if a higher scope over bore height will push the Maximum Point Blank Range further away from the shooter and shorten it slightly.

A lower scope position will bring the MBPR in closer to the shooter and the MPBR will lengthen slightly.

I just looked at a .177 profile I have in Chairgun. Not even sure what projectile it was but I'm only changing scope height and re-calculating Optimal Zero. Guessing it was a Polymag.

Scope over bore height of 1.5" gives an Optimal Zero of 31.6 yards and an MPBR of 11.5 to 34.8 yards (23.3 yard difference). That is with a 1/2" kill zone. The 1/4" high point of this range is just over 25 yards.

Scope over bore height of 2.5" gives an Optimal Zero of 36.2 yards and an MPBR of 17.1 to 39.3 yards (22.2 yard difference). Same kill zone. The 1/4" high point of this range is just over 30 yards.

While I also try to keep my scopes low, that has more to do with a comfortable cheek weld than anything else. If manipulating MPBR via scope over bore height was that important then I wouldn't be shooting Leshiys which tend to have higher scope over bore heights to begin with.

I have noticed that many springer custom stocks have higher cheek welds. Conversely, I have noticed that the factory stocks often have low cheek welds. It's what I like the least about my HW30 now that I think about it. If I were to get a custom stock for it I would strongly prefer an adjustable comb. If that weren't an option and the cheek weld was too high I'd just get taller rings and not worry about it.
 
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mtnGhost said:
I can't stand skyjacked scope rails. It makes the rifles top heavy and bulky. I'd rather take some slight mechanical disadvantage and run them as low as possible.
Click to expand...
Top heavy...

Like the stock comb hight and all some guns i sholder i think " man, did a real live adult person with any shooting experience in the R&D department ever shoulder this and see its not that good or just uncomfortable and say we need to change this a little ?". .... Or Somthing. Now i guess the computer says its good , make ship it, sell it. Blind
 
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Yes, it has been said the scope should be mounted as low as possible....for thousands of years by the powder burners,,, the thing is the magazines for those rifles are mounted Below whereas air guns' mags are mounted from the side, plus they are usually higher than the scope mount groves,
So air gunners usually need higher mounts because of the mag,or single feeding pellets with bigger than a child's fingers.
I have a giraffe neck thus I need higher mounts to be comfortable......
Bottom line is that I have never seen a problem for me with high mounts,hope I not sticking my neck out by saying so;)
 
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Jspool said:
Scouty, are you saying a MPBR with a 1/2” kill zone can maintain that kill zone over the 22 to 23 yrd range with no adjustment?
Click to expand...

Yes. The first number in my above examples are the near 1/4" low point. The second number is the far 1/4" low point. That's the MPBR. There is a point in between that is 1/4" high. I'll go back and edit my post with the 1/4" high point. Obviously there is also your Optimal Zero which is neither high nor low.

Jspool said:
Changing the height of the scope shifts that MPBR range closer or further?
Click to expand...

Raising the scope height pushes the MPBR further away. You see I ran the number for 1.5" and 2.5" scope over bore heights. I'll put those sections in bold once they're edited.

I will add that I almost always set up my airguns with Optimal Zero. I figure I'm always going to have holdovers near or far no matter what so I sure as heck don't want hold under anywhere in the middle of normal shooting distances.

I do have a backyard pest gun that is zeroed a bit closer than its Optimal Zero but I don't have shots long enough for that to be a problem. Shots that far would be well into the thick brush in the ravine behind my house.
 
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Jspool, explained for an 8inch target of a deers heart. Picture diagram

www.americanhunter.org

An Official Journal Of The NRA | How to Zero Your Rifle for Maximum Point-Blank Range

In a push to “go long,” it’s easy to add too much complexity to the hunt with the use of laser rangefinders, anemometers, spinning turrets and Christmas tree reticles. But you don’t have to touch your scope to shoot game out to 300 yards. Zero your rifle for its maximum point-blank range and...
www.americanhunter.org www.americanhunter.org
 
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The difference between mounting a scope high or low is mostly choosing between easier trajectory before or after your zero.

With a scope that is mounted close to the bore there is little holdover/dialing between the muzzle and your zero distance. With a scope that is mounted high above the bore shooting at distance is 'easier' because you need less elevation to hold/dial for the same far distance compared to a low mounted scope. Just a matter of pick your poison since both are fine, it's just where do you want your slight disadvantage to be
 
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dizzums said:
picture your barrel spitting a pellet out in an arc, draw an arc line .... now put your scope on top and draw a STRAIGHT line intersecting to 'skim' the arc ... the higher you move the scope up the further out that 'skim' point will be on the arc ...
Click to expand...
This graph may help.

BLl9Xl6h.png
 
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Most springers with custom stocks and high scope rails are set up to shoot WFTF at 12 FPE, which means they are clicking.
When you are clicking, the higher scope mount means less clicks for the longer targets. This gives more of a margin for error with the ranging. If you are a couple of yards off with the ranging, you will only be 2 or 3 clicks off instead of 10-15 clicks off.
On the other hand, you will have a lot more clicks for the close targets, but since those are easier to range, that's a good trade off. Field target in Europe is more of a long range game and they don't have our 3/8" kill zones for the close targets, so they tend to go high with the scopes.

My preference is to go as high with the scope as possible while keeping the full range of clicks from 10 to 55 yards on one scope rotation. I'm going to miss some long targets either way, but I hate to miss targets because the turret was a rotation out.
 
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