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The Easton 4mm FMJ in a 400 spine: 9.8 grains per inch,.204 in bore, the Easton 4mm Microlite nock it takes and the 8-32 thread. Suits a medium draw of roughly 45 to 65 lb. Sourced.

Updated 05 September 2026.

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Easton 4mm FMJ in a 400 spine: GPI, bore and nock

The 400 spine of the Easton 4mm FMJ: its exact GPI, the nock and thread it takes, and the draw it suits.

The Easton 4mm FMJ in a 400 spine weighs 9.8 grains per inch and suits a medium draw of roughly 45 to 65 lb. It takes the Easton 4mm Microlite nock its.204 in bore requires and the 8-32 point thread; confirm on the maker chart for your exact draw and length.
This spinemanufacturer data, cited
ModelEaston 4mm FMJ
BrandEaston
Spine400
Outside diameter.234 in OD
Weight9.8 GPI
Grains per inch9.8 GPI
Inside diameter.204 in
Stock nockEaston 4mm Microlite nock
Stock insertEaston 8-32 aluminium half-out (50 gr)
Point thread8-32
Straightness+/-.002 in (Match Grade +/-.001)
Suitsa medium draw of roughly 45 to 65 lb
The shaft

Easton 4mm FMJ carbon arrow shaft (400 spine)

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Field notes

This is the 400 spine of the Easton 4mm FMJ, a 4mm micro (aluminium jacket) shaft with a.204 in inside diameter. In this spine it weighs 9.8 grains per inch and measures.234 in OD across. A 400 spine sits at the mid range, the most common hunting-weight compound band.

Because the bore is.204 in, it takes the Easton 4mm Microlite nock and the Easton 8-32 aluminium half-out (50 gr), and it threads to the 8-32. Those do not change with spine; only the GPI and outside diameter move across the table.

Spine is a starting point, not a guarantee: a 400 from one brand can differ from another. Read your exact draw weight and arrow length on the maker chart or bare-shaft test before cutting a dozen, and keep the finished arrow above the 5-grains-per-pound floor.

Spec, chart, nock and concept

Easton 4mm FMJthe full shaft spec (250, 300, 340, 400)Easton 4mm FMJ spine chartwhich spine for your draw weightWhat an arrow spine number meanshow to read the deflection numberThe nock that fits this borepress-fit nock for the.204 in shaftThe 5-grains-per-pound floorkeep the finished arrow heavy enoughEaston 6.5mm Hunter Classicanother Easton shaft

Questions and answers

What is the model of the Easton 4mm FMJ in a 400 spine?

Easton 4mm FMJ

What is the brand of the Easton 4mm FMJ in a 400 spine?

Easton

What is the spine of the Easton 4mm FMJ in a 400 spine?

400

What is the outside diameter of the Easton 4mm FMJ in a 400 spine?

.234 in OD