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The Easton 5mm FMJ in a 300 spine: 12 grains per inch,.204 in bore, the 5mm X nock (9 gr) it takes and the 8-32 thread. Suits a heavy draw of roughly 65 lb and up. Sourced.

Updated 05 September 2026.

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Easton 5mm FMJ in a 300 spine: GPI, bore and nock

The 300 spine of the Easton 5mm FMJ: its exact GPI, the nock and thread it takes, and the draw it suits.

The Easton 5mm FMJ in a 300 spine weighs 12 grains per inch and suits a heavy draw of roughly 65 lb and up. It takes the 5mm X nock (9 gr) 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 5mm FMJ
BrandEaston
Spine300
Outside diameter.273 in OD
Weight12 GPI
Grains per inch12 GPI
Inside diameter.204 in
Stock nock5mm X nock (9 gr)
Stock insert5mm HIT insert (16 gr)
Point thread8-32
Straightness+/-.001 in
Suitsa heavy draw of roughly 65 lb and up
The shaft

Easton 5mm FMJ carbon arrow shaft (300 spine)

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Field notes

This is the 300 spine of the Easton 5mm FMJ, a 5mm class (.204 in ID) shaft with a.204 in inside diameter. In this spine it weighs 12 grains per inch and measures.273 in OD across. A 300 spine sits at the stiff end of the range, for heavy compound draws and heavier points.

Because the bore is.204 in, it takes the 5mm X nock (9 gr) and the 5mm HIT insert (16 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 300 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 5mm FMJthe full shaft spec (250, 300, 340, 400, 500)Easton 5mm 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 Bowhunteranother Easton shaft

Questions and answers

What is the model of the Easton 5mm FMJ in a 300 spine?

Easton 5mm FMJ

What is the brand of the Easton 5mm FMJ in a 300 spine?

Easton

What is the spine of the Easton 5mm FMJ in a 300 spine?

300

What is the outside diameter of the Easton 5mm FMJ in a 300 spine?

.273 in OD