Indians For Guns

MOUNTING SCOPES ON BREAK BARREL AIR RIFLES

INTRODUCTION
With the growing interest in Air Arms amongst our members and what with newer models entering the market, shooters are opting for mounting scopes on to their ARs to enhance their shooting pleasure.

Now shooting an Air Rifle with open sights & doing the same with a scope mounted on it, are two different aspects altogether. The reason being, in the case of Open Sights both the rear & front sights are mounted on the barrel of the AR, while a scope sits on its receiver.

Hence should there be any shift in the barrel alignment with the receiver such as barrel droop or canting, the centering of the scope will go for a toss resulting in the loss of accuracy.

CHOOSING THE RIGHT AIR RIFLE SCOPE

•Choosing the right air rifle scope can be a daunting task. There are dozens to choose from and all of them have different features to offer you. To make things easier, let’s examine the basics of Air Gun scopes. Essentially, a scope simply magnifies an image you are targeting and puts you on the same visual plane as the object. It does this by using a series of lenses inside the scope to bend the light that enters so that it magnifies the image.

•An air rifle scope is special because it can withstand the unique vibration and double recoil of an air rifle. NEVER PUT A FIREARM SCOPE ON AN AIR RIFLE. Now, the reason people enjoy having scopes on their air rifles is because it will help you achieve the pinpoint accuracy that air rifles are known for. So, let’s take a look at the two different kinds of scopes starting with fixed air rifle scopes.

FIXED POWER AIR RIFLE SCOPES

•A fixed air rifle scope is set on one magnification and cannot be adjusted. It is denoted by something like this: 4X32 or 4X15. The 4X means that the object in the viewfinder is magnified 4 times more than you can see with the naked eye. The advantage to having a scope like this is that once it is sighted in, it requires very little adjusting. The disadvantage is that you cannot magnify an image any more than the set magnification. These scopes are adequate for target shooting & plinking and hunting at ranges up to 40 yards.

VARIABLE AIR RIFLE SCOPES

•With this type of Air Gun scope, an image can be magnified usually between 2X – 7X, 3X-9XX, 4X-12X and so on. These will be denoted as something Eg: 3-9X32. This means you can magnify it 3 to 9 times and the 32 means a 32mm objective lens.

•These scopes are great for target shooting, plinking & hunting at longer distances. The disadvantage to this kind of scope is that it may require more frequent adjustments because of variable magnification, objective lens focus etc.

WHAT DOES AN OBJECTIVE LENS SIZE MEAN

•The last number in a scope description denotes the objective size. For example in a 4-16 X 50 Scope 50 means that this scope has a 50mm objective or a 50 mm lens opening. Objective size is important for two reasons.

1.The bigger the lens, the stronger the magnification.
2. Larger objective will allow more light to enter the scope giving you a brighter, clearer sight picture.

•If you plan to use your air rifle scope at dusk or in other low light conditions be sure to pick a scope with a large objective lens.

FIXING THE MOUNTS

•All scopes need a way to be attached to the gun, this is done by using a one or two piece scope mount that fit around the scope and are tightened onto a rail on top of the receiver of the Air Gun. It’s recommend using a one piece mount for break barrel spring air rifles that have a lot of recoil. A one piece mount is sturdy as compared to two piece mounts and can withstand the intense recoil of magnum air rifles.

•As a thumb rule Air Rifles with velocities varying between 475 fps & 600 fps a two piece mount will suffice. However for Air Rifles that’s capable of higher velocities such as 700 fps to 900 fps single piece mounts are ideally recommended.

TYPES OF MOUNTS

HIGH MOUNTS

•These rings work best with larger scopes because it allows them to sit higher on the gun, giving the large objective lens room to clear the stock and barrel. In most cases high mounts should be used for scopes with a 50mm objective or higher. Only use high mounts if you have a scope with a big objective. You should always try to mount the scope as low to the top of the rifle as possible as this will increase your accuracy.

MEDIUM MOUNTS

•These rings are slightly smaller than High rings and will work for most any air gun scope with an objective of 44mm or less.

ONE PIECE MOUNTS

•These mounts offer added stability to your scope. These mounts work best with high-powered rifles with a velocity of over 1000 fps. These mounts are a bit more expensive but a lot of shooters feel that it is worth it because of the added stability which means better accuracy.

NOTE:
Please bear in mind that “Mounting a Scope” needs the dexterity of a skilled Gunsmith as precision drilling and tapping are required, as any off-centre drilling & tapping or misalignment can ruin the receiver of your precious Air Rifle.

HAPPY SHOOTING!!!

Briha

Thank you very much sir for this information.....but I was wondering that if there is any other way of mounting a scope on an AR which is minus rails???????
Any inputs?????

Quote:
"WHAT DOES AN OBJECTIVE LENS SIZE MEAN

"The last number in a scope description denotes the objective size. For example in a 4-16 X 50 Scope 50 means that this scope has a 50mm objective or a 50 mm lens opening. Objective size is important for two reasons.

1.The bigger the lens, the stronger the magnification. "


No. The size of the objective does not determine the magnification. Magnification is a function of the eyepiece.

For years I used a scope on a Weihrauch HW 35 which kept moving out of position. I now realise that it was not an airgun scope - I had bought it at a garage sale in the UK. It has a two-piece mount

I read recently that a single piece mount is better for springers. Is that correct?

bennedose wrote:For years I used a scope on a Weihrauch HW 35 which kept moving out of position. I now realise that it was not an airgun scope - I had bought it at a garage sale in the UK. It has a two-piece mount

I read recently that a single piece mount is better for springers. Is that correct?

> YES! By all means
> Because the vibration (shock) of the AR both forward & backward is transferred uniformly & equitably along the same axis - thus ensuring stability.
Briha

Great thread Brihaji,
Thanks

Regards
TC

[quote="vivek16sep1969"]
Thank you very much sir for this information.....
but I was wondering that if there is any other way of mounting a scope on an AR which is minus rails

> AR receivers that come without milled grooves can be mounted with a scope by attaching a "Scope Rail" normally of 11mm width.
> Care should be taken re: proper alignment along with the 'line of sight'.
> Its recommended that a thin layer of any good epoxy cement (Araldite) be applied on the receiver as well as the bottom side of the scope rail prior to fastening it with screws. Roughening the surfaces by sanding will ensure better adhesion.
> Also ensure that the joining surfaces are de-greased / rid of any oil deposits by using either acetone or denatured spirit before fixing the scope rail.
Briha

Brihasir, as far as DIY mounting scope rails goes.......... my personal experience would be, unless you got very very steady hands, eyesight keen enough to judge 1 degree off-centre, and guts to combine the two, just don't try this at home!! Alas, I had only the last one!!! Araldite isn't easy to remove once set!

essdee1972 wrote:Brihasir, as far as DIY mounting scope rails goes.......... my personal experience would be, unless you got very very steady hands, eyesight keen enough to judge 1 degree off-centre, and guts to combine the two, just don't try this at home!! Alas, I had only the last one!!! Araldite isn't easy to remove once set!

Araldite can be removed - a bit of patience is reqd.
I did it by heating the joints by using a Pipe Lighter (It had an angular nozzle) and tapping the rail off the receiver
Normally once the scope rail is fixed it is for ever - it becomes integral to the receiver.
Briha

Fantastic! Finally a much needed thread on the subject...

Thank you Janaab Briha.

now for the big question -

Where can one purchase such scopes here in the County?

I hear that there is some kind of restriction on importing scopes, is it true?

This is a lovely topic you have started! Many youngsters, and I would say even people with firearms don't know how to go about this topic.

Please add another sub topic to you original post, namely, parallax correction. explaining why it occurs would be helpful too.

supershaji wrote:Fantastic! Finally a much needed thread on the subject...

Thank you Janaab Briha. now for the big question -
Where can one purchase such scopes here in the County?
I hear that there is some kind of restriction on importing scopes, is it true?

> Yes! There are restrictions on importing scopes into our country....
> The Only reliable source to buy scopes & mounts is our own fellow IFGian Rijo Joseph - You can PM him & give your requirement - Receive quote (his prices are reasonable) Transfer the money & within a week you'll get the scope + mount at your Door Step
> I have bought 2 scopes & mounts from him & only last week fellow IFGian essdee1972 got his! Many others have also got it from him.
Good luck & Happy shooting
Briha

brihacharan wrote:

supershaji wrote:Fantastic! Finally a much needed thread on the subject...

Thank you Janaab Briha. now for the big question -
Where can one purchase such scopes here in the County?
I hear that there is some kind of restriction on importing scopes, is it true?

> Yes! There are restrictions on importing scopes into our country....
> The Only reliable source to buy scopes & mounts is our own fellow IFGian Rijo Joseph - You can PM him & give your requirement - Receive quote (his prices are reasonable) Transfer the money & within a week you'll get the scope + mount at your Door Step
> I have bought 2 scopes & mounts from him & only last week fellow IFGian essdee1972 got his! Many others have also got it from him.
Good luck & Happy shooting
Briha

Rijo Joseph will be hearing from me soon indeed, but only after you have suggested to me a few options which would be suitable for the Precihole SX100 Orion please

Hi all
Came across this journal while searching to know more about scopes. While buying a scope we donot consider this factor but its still an important aspect to consider

Reticle focal plane


Typical internal construction of a scope with its reticle in the First Focal Plane.
Telescopic sights based on refracting telescopes using image erector lenses to present the user with an upright image have two planes of focus where a reticle can be placed: at the focal plane between the objective and the image erector lens system (the First Focal Plane (FFP)), or the focal plane between the image erector lens system and the eyepiece (the Second Focal Plane (SFP). On fixed power telescopic sights there is no significant difference, but on variable power telescopic sights a first focal plane reticle expands and shrinks along with the rest of the image as the magnification is adjusted, while a second focal plane reticle would appear the same size and shape to the user as the target image grows and shrinks. In general, the majority of modern variable-power scopes are SFP unless stated otherwise.

The main disadvantage of SFP designs comes with the use of range-finding reticles such as mil-dot. Since the proportion between the reticle and the target is dependent on selected magnification, such reticles only work properly at one magnification level, typically the highest power. Some long-range shooters and military snipers use fixed-power scopes to eliminate this potential for error. Some SFP scopes take advantage of this aspect by having the shooter adjust magnification until the target fits a certain way inside the reticle and then extrapolate the range based on the power adjustment. Some Leupold hunting scopes with duplex reticles allow range estimation to a Whitetail Buck deer by adjusting magnification until the area between the backbone and the brisket fits between the crosshairs and the top thick post of the reticle. Once that's done, the range be read from the scale printed on the magnification adjustment ring.

Although FFP designs are not susceptible to magnification-induced errors, they have their own disadvantages. It's challenging to design a reticle that is visible through the entire range of magnification: a reticle that looks fine and crisp at 24x magnification may be very difficult to see at 6x . On the other hand, a reticle that's easy to see at 6x may be thick enough at 24x to make precision shots difficult. Shooting in low light conditions also tends to require either illumination or a bold reticle, along with lower magnification to maximize light gathering. In practice, these issues tend to significantly reduce the available magnification range on FFP scopes compared to SFP, and FFP scopes are much more expensive compared to SFP models of similar quality. Most high-end optics manufacturers leave the choice between a FFP or SFP mounted reticle to the customer or have scope product models with both setups.

Variable power telescopic sights with FFP reticles have no problems with point of impact shifts. Variable power telescopic sights with SFP reticles can have slight point-of-impact shifts through their magnification range, caused by the positioning of the reticle in the mechanical zoom mechanism in the rear part of the telescopic sight. Normally these impact shifts are insignificant, but accuracy-oriented users, who wish to use their telescopic sight trouble-free at several magnification levels, often opt for FFP reticles. Around the year 2005 Zeiss was the first high-end European telescopic sight manufacturer who brought out variable magnification military grade telescopic sight models with rear SFP mounted reticles. They get around impermissible impact shifts by laboriously hand-adjusting every military grade telescopic sight. The American high-end telescopic sight manufacturer U.S. Optics Inc also offers variable magnification military grade telescopic sight models with SFP mounted reticles.
The economic grade scopes (for fixed & variable magnification) that we use have no issues with SFP or FFP. But people using high end scopes have to be more specific while buying the same. What say???
Regards Moulindu

Moulindu,

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