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Arrows & Components

What are the Limited/Premier straightness tolerances,what does that mean?

Altra Limited arrows have a straightness spec of 0.003’’, meaning every Limited will be at maximum 0.003’’ from perfect 0.000’’ straightness. Altra Premier arrows have a straightness spec of 0.001’’. In short, the lower the straightness spec tolerance, the straighter your arrow is.

How is straightness measured?

Each Altra Arrow has its straightness validated with the highest level of precision and accuracy using a custom-built machine that rotates and laser scans the arrow shafts to determine straightness. By having a hands-free process, human error and manipulation is eliminated – giving the most precise straightness data possible.

What components are included with arrows?

Altra 166 arrows include Altra nocks installed, and ARCOS components included. Altra branded Q2i RAPT-X vanes are installed on all fletched arrows.

Altra 246 arrows include Altra nocks installed, and inserts included. Altra branded Q2i RAPT-X vanes are installed on all fletched arrows.

Altra Target/3D arrows (Altra 23 and Altra 27) do not come with any components installed. Due to the highly customizability and capability of setting up the tournament arrows unique to each archer – the components must be purchased separately.

Are there recommended glues to use for components?

Low temperature hot melt can be used with caution on all components EXCEPT the ARCOS insert.  Hot melt is not recommended for this component as overflow during installation can attach to the O-ring which results in the O-ring being removed with excess hot melt, or it causes the O-ring to fail.  

  • Loctite super glue gel 
  • Pine Ridge Instant Arrow Glue 
  • Pine Ridge Insta Arrow Glue 
  • Pine Ridge Insert Glue 

**High temp hot melt is not recommended as the heat needed to melt the glue can compromise the integrity of the carbon arrow**

We recommend that you consult your preferred vane manufacturer for their recommended glue for fletching arrows. 

When using FMS insert weights, it is recommended that blue Loctite is used to secure them to the insert.   

Can I use other brand components on my Altra Arrows?

We strongly recommend using Altra Arrow components with your Altra arrows for the best fit, function and durability. Using components of other brands could result in a compromised arrow and would void any warranty or repair/replacement

What lighted nocks work for which arrow size?


  • GT- Altra Centrum 246
  • G-Altra Centrum 166


  • Lumenok GT- Altra Centrum 246
How do I know if my arrow is damaged?

Arrows should be checked for damage after each shot. We recommend checking components on each end of the arrow for potential damage, as well as checking the carbon arrow. To check the arrow for damage, visually look for any cracks or failures to the carbon along the shaft. You should also hold the arrow at each end and bend the arrow to a slight curve – when bending the arrow, listen for any crackling or noises and deformation of the carbon shaft.  If any of the above attributes are heard or
seen, replace components and/or discard the arrow.

What arrow size do I need?

Please review the differences between hunting/target arrows
and the pros/cons of each arrow size below:

Differences between hunting/target arrows:

Hunting arrows are generally smaller in diameter than target arrows for
the main purpose of increased penetration, reduced wind drift, and greater kinetic energy.

Pros/cons of each arrows size:

Your arrow size selection will depend on what you are trying to achieve with your arrow setup and which attributes are most important to you. Generally the following attributes are true:

Nock specs for string fitment 

All Altra nocks have a throat diameter of 0.110’’ for precise arrow-to-string fitment.

What kind of targets should I use?

Altra Arrows highly recommends using a foam style arrow target when shooting arrows that have an ARCOS system, as the outserts can get stuck in filler of bag style targets which can damage the insert/outsert system or arrow.

Arrow Spine

What is ‘NO SPINE Technology’?

Spine is used to describe 2 things in relation to an arrow. One definition is the stiffness of the arrow and how much it deflects under load like stated above. The other definition of spine in relation to an arrow, is the stiff axis that runs the length of the arrow shaft – that is what Altra’s ‘No Spine Technology’ refers to.  Our sophisticated manufacturing processes essentially eliminate that stiff axis(spine) of the arrow, resulting in an arrow shaft with a uniform stiffness 360 degrees rather than having an axis that is stiffer than the rest of the arrow shaft. In doing this, a far superior arrow is created, eliminating the need for spine indexing your arrows so that the stiff axis aligns vertically.  This uniformity results in an arrow that is much easier to tune with increased downrange accuracy.

How do I determine what spine arrow I need?

Please review the Altra Spine chart to determine the recommended arrow spine based on your draw weight and draw length.

How is the spine of an arrow determined?

The spine of an arrow is determined by placing an arrow on a spine tester so that it is supported at a fixed span of 28 inches, then the arrow is deflected by placing an 880-gram weight in the center and measuring the amount that the arrow deflects in inches. For example, if an arrow is deflected in this process and it deflects .300” then it would be a 300-spine arrow.

How long should my arrows be?

Arrow length is specific to your shooting setup.  To determine arrow length, we recommend that you nock an arrow, draw your bow and have a friend mark your desired length; ideally no closer than the middle of the riser shelf. The length of your arrow along with selected components will affect the arrow’s dynamic spine. See specifics for each Altra Arrow type with components below:


Due to the A.R.C.O.S. system extending the overall arrow length, we recommend cutting arrows 1.25" shorter than your normal personal desired total arrow length.  This will result in arrows with the A.R.C.O.S. system installed being your desired length. Please note that the A.R.C.O.S. outsert will overlap the front of your arrow by0.43"which should be considered when determining arrow length so that it does not cause interference with your arrow rest.


Both the standard and heavy brass 246 inserts have a lip thickness of 0.83’’ which will increase your total arrow length by that much.


Target/3D arrow lengths should be determined as mentioned above. Nocks can be installed via bushings on the back end of the arrow but can be cut slightly shorter if preferred since they do not need broadhead clearance.

What is dynamic spine?

Dynamic arrow spine is the spine of the arrow during the shot. There are many factors that affect the dynamic spine of the arrow such as arrow length, component weight, draw length and draw weight. An arrow’s dynamic spine can be adjusted by changing the weight of arrow components or the length of an arrow.

Are components model specific?

Yes. There are some components such as vanes and nocks that can be used across multiple arrow sizes. All machined components are arrow size specific, and even further, the Centrum 166 components are spine specific to create the most precise arrow-to-component fitment. All arrow pages will have the affiliated components that can be used with them listed.


What is FOC (front of center)?

Front of Center (FOC) is a term commonly used in archery and arrow design. It refers to the central balance point of an arrow in relation to its overall length. FOC is a critical factor in determining an arrow’s flight characteristics, down range accuracy, and penetration performance.

The FOC measurement is calculated as a percentage of the total arrow length, starting from the tip of the arrow. A higher FOC % means more weight is concentrated towards the front of the arrow, while a lower FOC means more weight is distributed towards the rear. The FOC value is influenced by various factors, including the weight of the arrow itself as well as installed components and their position along the arrow shaft.

Having the appropriate FOC % for a specific type of archery and arrow usage is essential for achieving optimal arrow flight and performance:

  1. Traditional bows – a higher FOC % (10-15%) is often preferred, which helps to stabilize the arrow in flight ultimately making it less prone to planing or erratic flight.
  2. Compound bows – a lower FOC %, compared to traditional setups, (7-10%) is usually preferred. The additional technologies and features of compound bows allow for better arrow flight and down range accuracy without requiring as much front-end weight.
  3. Hunting – in hunting situations, some archers prefer a slightly higher FOC to enhance arrow penetration and stability during impact.
  4. Target/3D – archers may vary their FOC based on their personal shooting style and preferences.
How do I measure FOC?

First, divide the total length of the arrow by two. Then, find the balance point – the balance point is the point on the shaft at which you can balance the arrow without issue (usually towards the front of the shaft). The balance point measurement will be from the balance point to the back of the arrow. Then, subtract the distance from the nock end to the center from the balance point. Multiply this number by 100, and then divide it by the total length of your arrow. See equation below for visual reference:

How is kinetic energy calculated?

KE = velocity (FPS) squared multiplied by arrow mass(grains) divided by 450240
KE=(mv^2)/450240 m = arrow mass in grains v = velocity of arrow out of bow
Ex: a 450 grain arrow shooting 280 FPS
(280^2*450)/450,240= 78.4 ftlbs KE

What is GPI?

GPI stands for ‘Grains Per Inch.’ GPI is a standard measurement of arrows in the archery industry to indicate the weight of an arrow shaft per inch of length. GPI is an essential specification when choosing arrows because it directly affects their performance and compatibility with your bow. GPI will affect your arrow speed and dynamic spine.

GPI = Arrow Shaft Weight (grains) / Arrow Shaft Length (inches)

How to tune broadheads?

Tuning broadheads is an essential process in archery to ensure that they fly accurately and consistently with your arrows. Broadhead tuning involves adjusting your bow and arrow setup to achieve proper arrow flight. Here is a step-by-step guide on how to tune broadheads:

  1. Ensure Proper Arrow Spine: Make sure that your arrows have the correct spine (stiffness) for your bow's draw weight and draw length. Arrows with an incorrect spine may not fly well with broadheads.
  2. Consistent Nocking Point: Check that the nocking point on your bowstring is consistent. A level and correctly positioned nocking point helps maintain arrow flight consistency.
  3. Consistent Arrow Nocks: Ensure that the nocks on your arrows are all the same type and weight, and that they are installed consistently. This helps eliminate variations in arrow flight.
  4. Paper tuning: This is a good starting point to get your bow and arrows tuned, or close to tuned, before moving on to broadhead tuning. This can be done with either a bare shaft or fletched shaft with field points. Tune your bow and arrows to achieve a bullet hole or close to bullet hole through paper. (Follow your specific bow manufacturers manual or consult with a professional bow tech for this process).
  5. Achieving the same impact with Field Points and Broadheads: Start by sighting in a fletched arrow with field points at 20 yards. Once you are sighted in, shoot an arrow with your desired broadhead, then follow up with an arrow that has a field point. Adjust your rest and nocking point to achieve consistent impacts between the two arrows. If the broadhead arrow hits to the left or right of the field point arrow, adjust your arrow rest accordingly. If they hit high or low, adjust the nocking point or rest elevation. For example, if the broadhead impacts left of the field point, move your rest to the left until both arrows are impacting together. To achieve an even finer tune, this same process can be repeated over longer distances.
  6. Broadhead Alignment: Once you have achieved good broadhead tuning, mount your broadheads on the arrows. Ensure that the broadhead blades are aligned with the fletching's and the arrow shaft. Misalignment can cause erratic flight.
  7. Fine-Tuning: Make minor adjustments as needed to achieve tight and consistent groups with your broadheads. This may include further adjustments to the arrow rest, nocking point, or bow sight.
  8. Practice and Fine-Tune: Spend time practicing with your tuned broadheads to gain confidence in their accuracy. If you notice any issues during practice, reevaluate your setup and make additional adjustments if necessary.

Remember, broadhead tuning may require some patience and trial-and-error. It is essential to take your time and make incremental changes to achieve the best results. If you are unsure about tuning your broadheads yourself, consider seeking help from an experienced archery coach or a professional bow technician.

Specs of Altra fletched arrows

Our fletched arrows have the same straightness, spine, and GPI specs as our non-fletched arrows. All hunting arrows come preinstalled with Altra nocks and Altra branded Q2i RAPT-X vanes in a 3 fletch, 2 degree right offset orientation.


What vanes should I use, what length, etc.?

We recommend fletching Altra Arrows with the Altra branded
Q2i RAPT-X vanes.

Vanes, offset, shaft cleaning/prep

It is recommended that arrow shafts are wiped down with alcohol prior to fletching to remove any grease or particles that may interfere with adhesion between vanes and the shaft. Vane size, shape, orientation(straight/offset/helical/etc), and quantity are specific to your goals for your archery setup.

Is a primer needed for our Altra Q2i RAPT-X vanes?

Q2i Archery is an industry leader for vanes in the archery arrow segment. Q2i vanes offer a top of class adhesion and their messaging states that a primer is not needed for maximum arrow-to-vane adhesion.

How do I use the FMS insert weights and weight tool?

The FMS weights are segmented into 2 sizes- micro and non-micro. The micro weights will work on all 166 arrow components (inserts & points) and the non-micro weights will work on all components larger than 166.


O-ring installation to ARCOS insert

Replacement O-rings come with an O-ring installation tool included. Simply place the recessed portion of the tool over the threaded portion of the insert. Then take an O-ring and slide over the tip of the O-ring installation tool; roll the O-ring downward until the O-ring nests into the recessed area on the insert. This completes O-ring installation.

What does the O-ring do?

The O-ring is a multi-purpose component of the A.R.C.O.S.

  • Aids in concentricity between the insert and outsert.
  • As the system gets tightened the O-ring compresses, which helps lock the outsert in place and helps reduce loosening of the outsert from the insert.
  • It has vibration and dampening properties, resulting in less stress on the A.R.C.O.S. system and arrow.
What is the difference between a pin nock bushing and standard uni-nock bushing?

An arrow bushing is a component that secures a nock to your arrow when the arrow inner diameter is larger than the nock outer diameter. A uni-nock bushing has a center bore that allows Altra standard size nocks to be used. A pin nock bushing has a small post that extends from the back side in which the Altra pin nock slides over and secures to that post, rather than sliding inside of a bore like a standard bushing. Which to select for your arrow setup is preferential.

Recommended Outer Diameter field point sizes per arrow


5/16’’ recommended for Altra Arrows using the A.R.C.O.S. system. All Altra .166 glue in points are available in 2 sizes (250-300 and 350-400 spine) and are designed specifically for your selected spine.


5/16’’ recommended for Altra Arrows standard or heavy brass .246 inserts. All Altra 246 glue in points are designed specifically for your selected spine.


Recommended to use the available Altra 23 glue in points


Recommended to use the available Altra 27 glue in points

Removing Components

How to remove vanes from arrows?

We recommend using a vane removal tool such as the Q2i Zip Strip or OMP Vane Stripper Tool. This tool safely removes old vanes and glue without damaging the arrow shaft or installed components. Once the vanes and glue are removed, we recommend wiping the shaft down with alcohol to remove any grease or particles that may interfere with maximum adhesion of your new vanes.

How to remove/replace components from arrows?

Nocks can be easily removed/replaced by pulling out the current nock. Simply, pull outward and twist at the same time. New nocks can be reinstalled using the same motion.

Components that were installed with low temperature hot melt can be removed by carefully using a heat source such as a torch. Heat the component, which will in turn soften the hot melt enough for you to pull the component out using pliers. We do not recommend trying to remove components that were installed with high temperature hot melt, super glue, or epoxies – as the amount of indirect heat needed to compromise the glue will damage the carbon shafts, resulting in an unsafe arrow.

Most of the time if a component is damaged bad enough to need replacing, then the arrow is also damaged and unsafe to continue using.

Still have questions?

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