The Franklin Armory F17-L complete upper receiver in .17 WSM (brand part no. 00-40072-BLK) drops onto a Milspec AR complete lower and turns it into a flat-shooting pest-control rifle. Franklin Armory chambers it in .17 Winchester Super Magnum and pairs a 20-inch threaded barrel with a piston-driven action for cleaner running. The new Osprey Defense slim piston adjusts on its own for suppressed or unsuppressed use, and it functions with most suppressors. The black finish and optic-ready design make it a finished upper from the box.

Key Specifications

• The chambering is .17 WSM, a flat-shooting cartridge aimed at varmint and pest control.
• The barrel is 20 inches long, the longer of the two F17 uppers, which squeezes more velocity from the cartridge.
• The muzzle is threaded 1/2×28, the common pitch for compatible suppressors.
• The twist rate is 1:9, matched to the .17 WSM bullet.
• The OPS piston gas system from Osprey Defense adjusts automatically for suppressed or unsuppressed use, with no adjustments needed.
• The gas block is a low-profile design that keeps the front of the barrel clean and uncluttered.
• The 15-inch handguard has an integrated barrier stop and indexing point and is M-LOK compatible, so accessories mount directly.
• The muzzle device is an Aura, supplied on the barrel from the factory.
• The bolt carrier is the F17 proprietary design built for the .17 WSM cartridge.
• The sights are listed as optic ready, so a scope or red dot mounts without extra rail work.

Frequently Asked Questions

Which lower does the F17-L upper fit? Franklin Armory says the complete upper comes with everything you need to install it on your Milspec AR complete lower receiver.

Can I run a suppressor on it? The 20-inch barrel is threaded 1/2×28, the common pitch for compatible suppressors. The OPS piston system adjusts automatically for suppressed or unsuppressed use.

What is the difference between the F17-L and the F17-X upper? The F17-L has the 20-inch barrel, while the F17-X uses a 16-inch barrel. Both are threaded 1/2×28 and chambered in .17 WSM.

Buy the Franklin Armory F17-L Complete Upper Receiver

A complete upper means you are not hunting down a handguard, gas system or bolt carrier to finish the build. This F17-L arrives assembled in .17 WSM with the long 20-inch barrel, ready for an AR lower you already own. See more AR-15 uppers and order it from our Lubbock, Texas gun shop for fast, insured shipping.