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Easton 4mm FMJ (4mm micro (aluminium jacket)): published spine and grains-per-inch table, the Easton 4mm Microlite nock it takes, its insert and the 8-32 point thread. Spines 250, 300, 340, 400.

Updated 05 September 2026.

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Easton 4mm FMJ: spine, diameter and nock fitment

The published spine and GPI table for the Easton 4mm FMJ, the nock and insert it takes, and the point thread.

Published shaft specmanufacturer data, cited
Class4mm micro (aluminium jacket)
Inside diameter.204 in
Straightness+/-.002 in (Match Grade +/-.001)
Stock nockEaston 4mm Microlite nock
Stock insertEaston 8-32 aluminium half-out (50 gr)
Point thread8-32
Spine 25012.3 GPI,.247 in OD
Spine 30011.7 GPI,.244 in OD
Spine 34011.0 GPI,.240 in OD
Spine 4009.8 GPI,.234 in OD
The shaft

Field notes

The Easton 4mm FMJ is a 4mm micro shaft with a carbon core inside a drawn 7075-alloy metal jacket, taking a 4mm Microlite nock and the 8-32 aluminium half-out.

Its published spines run from 250 at 12.3 grains per inch to 400 at 9.8 grains per inch, the metal jacket making it heavy for its diameter and high in front-of-centre.

The half-out carries the standard 8-32 point thread, so standard field points and broadheads fit; the Match Grade version is sorted to +/-.001-inch straightness.

Nock, thread, chart and more

Questions and answers

What is the class of the Easton 4mm FMJ?

4mm micro (aluminium jacket)

What is the inside diameter of the Easton 4mm FMJ?

.204 in

What is the straightness of the Easton 4mm FMJ?

+/-.002 in (Match Grade +/-.001)

What is the stock nock of the Easton 4mm FMJ?

Easton 4mm Microlite nock