Altra Centrum 166 Limited Arrows — .003 (6-Pack)
Altra Centrum 166 Limited Arrows — .003 (6-Pack)
Altra Arrows Centrum Limited line has exhaustive attention to detail with a straightness spec of up to 0.003?? for unmatched precision. State-of-the-art measuring equipment is used to verify arrow shaft and component straightness, along with Altra?s weight matching process, ensuring you are getting the most consistent arrows available. Manufactured from a proprietary blend of high modulus carbon this sophisticated construction results in Altra Arrows NO SPINE Technology, delivering an unrivaled arrow with improved tunability and increased consistency. The shafts are accompanied by premium components made from high grade aluminum and stainless steel.
- Comes in 12 pk Shafts QTY
- All arrow packages are weight matched to be +/- 1 gn
- 32" Total Length
- Components Not Included
- Available in sizes: 250, 300, 350, 400
Specifications and what they build
Everything below is either the manufacturer's published specification or this engine's output for a standard build — a 28.5″ finished arrow, 100‑grain point, HIT‑style insert, three vanes at 2° helical, on a 70 lb / 29″ compound rated 335 fps IBO. Nothing here is a rule of thumb and nothing is copied from a chart.
Altra 166 CENTRUM Limited — inner diameter class .166, outer diameter .166", premium hunting shaft. Limited-tier Centrum .166 micro-diameter hunting shaft. Removed fabricated 200 spine. GPI corrected & verified 2026-06 vs manufacturer.
| Spine | Stocked here | GPI | Outer diameter | Bare shaft, 28″ (gr) | Finished arrow (gr) | Speed (fps) | KE (ft‑lb) | FOC |
|---|---|---|---|---|---|---|---|---|
| 250 | yes | 11.8 | — | 330.4 | 475 | 273 | 79 | 10.7% |
| 300 | yes | 10.5 | — | 294.0 | 438 | 288 | 81 | 11.6% |
| 350 | yes | 9.4 | — | 263.2 | 406 | 301 | 82 | 12.5% |
| 400 | yes | 8.5 | — | 238.0 | 381 | 312 | 82 | 13.4% |
Which spine you need
Spine is not a property of the shaft you like, it is set by your draw weight, your finished arrow length and your point weight acting together. Read your draw weight down the left and your finished arrow length across the top. Green means this product is stocked in that spine, amber means the shaft is made in it but we do not stock it, red means this shaft is not made in that spine at all and you want a different one.
| Draw weight | 26″ | 27″ | 28″ | 29″ | 30″ | 31″ | 32″ |
|---|---|---|---|---|---|---|---|
| 50 lb | 400 | 340 | 340 | 340 | 340 | 340 | 340 |
| 55 lb | 340 | 340 | 340 | 340 | 340 | 300 | 300 |
| 60 lb | 340 | 340 | 340 | 340 | 300 | 300 | 300 |
| 65 lb | 340 | 340 | 300 | 300 | 300 | 250 | 250 |
| 70 lb | 340 | 300 | 300 | 300 | 250 | 250 | 250 |
| 75 lb | 300 | 300 | 250 | 250 | 250 | 200 | 200 |
| 80 lb | 300 | 250 | 250 | 250 | 200 | 200 | 200 |
The grid assumes a 100‑grain point. Going heavier up front weakens dynamic spine and pushes you one column left; going lighter pushes you right. The spine what-if tool publishes every coefficient behind this table, including how closely it agrees with Easton's, Victory's and Gold Tip's own charts.
What it is cleared for
Graded against the five energy floors we publish, each tagged with whose number it is — three are Easton's charted figures, two are ours and labelled as ours. The full reasoning, with the archive citations for the chart Easton retired in 2012, is on the kinetic energy chart by game class.
| Spine | KE (ft‑lb) | Small game 15 · judged |
Deer / antelope 25 · charted |
Elk / bear / boar 42 · charted |
Heavy game 50 · derived |
Big game 65 · charted |
|---|---|---|---|---|---|---|
| 250 | 79 | clears | clears | clears | clears | clears |
| 300 | 81 | clears | clears | clears | clears | clears |
| 350 | 82 | clears | clears | clears | clears | clears |
| 400 | 82 | clears | clears | clears | clears | clears |
Target size matters as much as energy — broadside vital dimensions for 61 species are on the vital zone page.
▸ Open this shaft in The Forge — free, loads at 350 spine with the standard build above, and every number recomputes as you change it.
Common questions
Which Altra 166 CENTRUM Limited spine do I need?
Read it off the grid above rather than off the bow's name: at 60 lb and 28 inches it picks 340, which this shaft is not made in, at 70 lb and 29 inches it picks 300, which is stocked, and at 80 lb and 30 inches it picks 200, which this shaft is not made in. Spine is set by draw weight, finished arrow length and point weight acting together. This product is stocked in 250, 300, 350, 400 spine.
What does the Altra 166 CENTRUM Limited weigh per inch?
GPI runs from 8.5 in 400 spine up to 11.8 in 250. A bare 28-inch shaft is therefore 238.0 to 330.4 grains before any components go on. Those GPI figures are the manufacturer's published numbers, not our estimates.
What is the outer diameter of an Altra 166 CENTRUM Limited?
It changes with spine, which is the part most charts leave out. This shaft spans .166". The inner diameter class is .166, and that is the number that decides which inserts, collars and nocks fit.
How heavy is a finished arrow built on an Altra 166 CENTRUM Limited?
On the standard build we use for every comparison — a 28.5-inch arrow, 100-grain point, HIT-style insert and three vanes at 2 degrees helical — this shaft finishes at 381 grains in 400 spine and 475 grains in 250, with FOC running 13.4 percent down to 10.7 percent as the shaft gets heavier. A stiffer spine gives you a heavier, slower, higher-momentum arrow; a weaker one gives you speed and higher FOC at the same point weight.
Is an Altra 166 CENTRUM Limited enough arrow for elk?
At the standard build the spines here make 79 to 82 ft-lb, against the 42 ft-lb floor Easton charted for elk, black bear and boar. Every one of them clears it. That 42 is Easton's number, not ours. Energy is a floor rather than a plan, though: on elk, momentum and FOC do as much of the work as kinetic energy, and these builds sit at 0.53 to 0.58 slug-fps.
Where do these numbers come from?
GPI, outer diameter and inner diameter are the manufacturer's published specifications. Our verification note for this shaft reads: Limited-tier Centrum .166 micro-diameter hunting shaft. Removed fabricated 200 spine. GPI corrected & verified 2026-06 vs manufacturer. Everything else on this page is computed by the same physics engine that runs The Forge — IBO-corrected launch speed for the stated draw weight, draw length and finished arrow mass, Easton-method kinetic energy and momentum, and a spine model published in full alongside its measured agreement with each manufacturer's own chart.
Specifications are the manufacturer's published figures; every derived number is this engine's output, reproducible from the inputs stated above. If a spec here disagrees with the manufacturer, the manufacturer is right and we want to hear about it.