TACFUN 3-9×42 Long Eye Relief Scope Review
By Amis Thains Updated 5 min read
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You want a scope that keeps your eye safe from recoil and lets you acquire targets quickly, but most optics don't offer enough clearance for scout-style mounts. This review breaks down the TACFUN 3-9×42's long eye relief features and how it performs on air rifles and centerfire scout setups.
In short: The TACFUN 3-9×42 is a solid choice for shooters needing extended eye relief. It offers 8.5 to 10.5 inches of clearance, is built from one-piece aluminum for durability, and includes flexible mounting options. It works well for air rifles where the scope is mounted further forward than traditional optics.
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Provides 8.5-10.5 inches of eye relief in a durable, nitrogen-filled housing with green glass.
Offsets the scope forward to create the necessary eye relief on scout rifles and air rifles.
What you need for a long eye relief setup
A long eye relief scope requires specific mounting hardware to function correctly. You cannot simply use a standard ring stack directly over the action; you need to push the optic forward. If that sounds like your bench, read up on gamo air rifle comparison next.
- Long eye relief scope: The TACFUN 3-9×42 or similar.
- Offset or cantilever mount: Moves the scope forward to create the eye relief gap.
- Rifle with scout mounting options: Air rifles, Mosin Nagants, or M1A/M4 style scout mounts.
The key here is the mount. If you use a standard Weaver ring on an air rifle, you will not get the long eye relief benefit. You need a device that attaches to the receiver or a forward position and holds the scope away from the breech.
This slim offset cantilever mount holds a 30mm scope forward, creating the long eye relief distance the TACFUN requires.
- Scope mount for mounting standard 30mm or 1 inch tube scopes (With Inserts)
- Solid construction with precision CNC machining
TACFUN 3-9×42 build and features
The TACFUN 3-9×42 is built from a single piece of aircraft-grade aluminum. This makes it tough enough to handle the recoil of heavier rifles, though it is a common choice for air rifles because of its weight and size.
Eye Relief: The scope is designed with a long eye relief of 8.5 to 10.5 inches. This is the main feature. It allows your eye to sit further back from the glass than a standard scope (which usually offers 3.5 to 4 inches).
Optics: It uses green fused multi-coated lenses. Green glass reduces eye strain in low light and provides good contrast. The scope is nitrogen-filled and sealed, so it will not fog up in rain or cold weather.
Turrets: It includes windage and elevation adjustments with a user-friendly pull-out knob for unlocking. This makes it easier to dial in your zero and keep it there.
This is the main scope reviewed, featuring the one-piece aluminum build and 8.5-10.5 inch eye relief.
- Milled from one solid piece of aircraft grade aluminum to withstand constant heavy
- Fog proof and shock-resistant housing; Nitrogen charged with weather resistant seals
Installing the scope on an air rifle
Installing a long eye relief scope on an air rifle is different from a centerfire rifle. You often have less space to work with, and the mounting method is critical. If that sounds like your bench, read up on preventing rust on guns next.
- Choose your mount point: Most air rifles use a top rail or a scout mount interface. If you are using a scout mount, attach it to the forward part of the rifle or a dedicated rail ahead of the action.
- Position the mount: Slide the mount so the scope is far enough forward to give you the 8.5-10.5 inch eye relief. Your eye should not be too close to the rear lens.
- Secure the rings: Use the included Weaver/Picatinny rings or your cantilever mount. Hand-tighten all screws first.
- Final torque: Use a torque wrench to tighten the screws. Do not overtighten; this can crush the scope tube or strip the air rifle’s aluminum housing.
If you are mounting on a standard air rifle top rail, the long eye relief might make the scope stick out far behind the rifle. This is normal, but you must ensure it does not hit the stock or your cheek.
If you are using a Ruger 10/22 or similar rimfire with a top rail, this mount and ring set simplifies the installation of a 30mm scope.
- ✔ All-in-One Solution: Includes Ruger 10/22 rail mount + 30mm scope rings for seamless
- ✔ Premium Aircraft Aluminum, Solid & Durable: Precision machining of aircraft grade
How the long eye relief feels and works
The main benefit of long eye relief is speed and comfort. When you acquire a target, you do not have to put your eye in a fixed, tight spot. You can sweep the scope quickly across a zone and still see the reticle.
Eye Box: The TACFUN 3-9×42 has a large eye box. This means you can be slightly off-center behind the scope and still see the full reticle. This is very helpful for air rifles where you might shift position slightly between shots.
Recoil Safety: On centerfire scout rifles, this prevents the rear lens from striking your eye. On air rifles, it reduces the chance of getting kicked by the stock if your eye is not perfectly aligned.
Clarity: The green lenses are clear and bright. The 3x to 9x zoom range gives you plenty of options. 3x is great for close-range air rifle plinking, while 9x helps for target practice at longer distances.
Pro tip: Practice sweeping your eye from left to right across the target while keeping the scope on your rifle. You should see the reticle remain in your view across a wide area due to the long eye relief. The other half of this decision is scope alignment for airguns.
Common mistakes to avoid
- Using standard rings on a scout mount: This does not create the necessary eye relief. You need a cantilever or offset mount to push the scope forward.
- Overtightening on air rifles: Air rifle bolts are often made of softer aluminum than rifle actions. Use a torque wrench and stop when the screws seat; do not force them.
- Ignoring the weight: The TACFUN is 14.5 oz. On a lightweight air rifle, this can make the gun nose-heavy. Balance it by adjusting your cheek weld or using a lighter mount.
- Not zeroing at a distance: Long eye relief scopes can be tricky to zero if your eye position varies. Mark your eye position on the stock or use a consistent cheek weld when zeroing.
Safety first: Always keep the muzzle pointed in a safe direction. When adjusting the scope on an air rifle, ensure the gun is unloaded and the safety is on.
The bottom line
The TACFUN 3-9×42 is a strong value for shooters who want a durable, long eye relief scope for air rifles or scout setups. Its one-piece build and large eye box make it easy to use. Pair it with a cantilever mount to get the full benefit of the extended eye relief.
- Milled from one solid piece of aircraft grade aluminum to withstand constant heavy
- Fog proof and shock-resistant housing; Nitrogen charged with weather resistant seals
Frequently asked questions
Can I use the TACFUN 3-9×42 on a .22 air rifle?
Yes, it works well on .22 air rifles. The long eye relief allows you to mount it further forward on the rifle, which is common for scout-style air rifles. Ensure you use a mount that is rated for air rifles and does not require removing the stock.
What is the difference between long eye relief and standard eye relief?
Standard eye relief is usually 3.5 to 4 inches, requiring your eye to be very close to the rear lens. Long eye relief is 7 inches or more, allowing your eye to sit further back. This is better for quick target acquisition and recoil safety.
Does the TACFUN 3-9×42 come with mounting rings?
Yes, it typically comes with Weaver/Picatinny rings and sometimes M44/M91 scout mount hardware. However, to achieve true long eye relief on many air rifles, you will likely need to add a cantilever or offset mount to push the scope forward.