FN SPR: Barrel

I took a short break from updating the blog since it is the only break I will get before my summer semester. I have not been idle and took a few short courses during the break. But now we need to look at the FN project again.


The setup work on the barrel is a repeat of everything that I did for the Mauser and Remington projects. After centering the barrel in the lathe, I cut the tenon and threaded the barrel to fit the receiver. The next step was to cut the cone for the bolt.

Cutting the cone

Cone complete

With the cone completed, I cut the chamber in the barrel. This rifle is chambered for .243 Winchester.  I tightened the action onto the barrel and it is now ready for test fire.

It fits!

Bolt open


Bolt closed

Time to do the test fire!

Test fire 1

Test fire 2

I am pleased with the test fire results. Case expansion on this rifle was 0.0005″ (12.7 microns/0.0127 mm). The final step of the barrel process is to cut the groove for the extractor. I marked the location of the barrel relative to the action, removed the barrel and set the barrel in a mill to cut the extractor slot.

Starting the extractor cut


During the cut

After I completed the cut, I re-assembled the action and barrel and verified the headspace and made sure the extractor works.

All lined up!

The only work left for the barrel is to do the crown. I will cover that in the next post on this project. As always, thank you for reading.


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