Talyn
Emissary
Foxtrot Mike ISU-9 Makes Standard 9mm Go Subsonic
This TFB article explains how the operating system of the Foxtrot Mike's ISU-9 upper receiver does this. Everything builds on the VFM-9 upper, with an ultra-slim handguard carrying 28 full-size M-LOK slots, and standard M-LOK hardware installs without pulling the handguard or suppressor apart.The barrel has precision-drilled ports that bleed expanding gas into the suppressor while the bullet is still travelling down the bore. That does two things at once. It cuts the pressure spike that drives a blowback bolt backwards, and it robs the bullet of velocity, which is why the ISU-9 can take ordinary 115 gr or 124 gr 9mm below the sound barrier without buying dedicated subsonic ammunition.
The bled gas then runs through an internal labyrinth, expands into a chamber surrounding the barrel, passes through a baffle stack and exhausts forward through ports in the flash-suppressor end cap.
Rather than fighting the back pressure a suppressor creates, the design uses it to help drive the action, which means less bolt and buffer mass is needed and the recoil impulse softens accordingly.
Foxtrot Mike ISU-9 Makes Standard 9mm Go Subsonic
A suppressed 9mm PCC is one of the most enjoyable things you can shoot.Subsonic from the muzzle, no blast, no ear defenders strictly required, and a rifle you can run flat and fast all day.The catch has always been the operating system.
www.thefirearmblog.com
The ports are drilled to intersect the lands of the rifling rather than the grooves, which is the difficult way to do it and the reason Foxtrot Mike claims accuracy survives the porting intact.
Integrally suppressed uppers normally sit well into four figures, but the ISU-9 has an MSRP of $499.
Foxtrot Mike ISU-9 the details:
- Integrally suppressed 9mm upper receiver, built on the VFM-9 platform
- Patented barrel-porting and gas-management system, eight years in development
- Ports intersect the lands of the rifling to preserve accuracy
- Uses suppressor back pressure to help drive the action, reducing reciprocating mass
- Brings conventional 115 gr, 124 gr and heavier 9mm to subsonic velocity
- Ultra-slim handguard with 28 full-size M-LOK slots
- M-LOK hardware installs without removing the handguard or suppressor
- Forward-charging and mil-spec AR charging handle compatible
- Transferable lifetime warranty
- MSRP $499, sold through Foxtrot Mike, Primary Arms and Silencer Shop
ISU-9 INTEGRALLY SUPPRESSED 9MM UPPER RECEIVER
FM PRODUCTS ISU-9 INTEGRALLY SUPPRESSED 9MM UPPER RECEIVER for sale from FM Products.
store.fm-products.com
Foxtrot Mike Products ISU-9 9mm Integrally Suppressed Complete AR9 Upper Receiver - 10"
The Foxtrot Mike Products ISU-9 is an integrally suppressed 9mm upper receiver with a 10" barrel, built around FM Products' patented suppressor system.
www.primaryarms.com
Foxtrot Mike Products Introduces the ISU-9: Redefining Integrally Suppressed 9mm PCC Technology - The Outdoor Wire | The Outdoor Wire
Foxtrot Mike Products announces the ISU-9 Integrally Suppressed 9mm Upper Receiver, featuring eight years of patented suppressor development. The innovative system reduces recoil and reciprocating mass while delivering exceptional accuracy at an MSRP of $499, available through Foxtrot Mike...
www.theoutdoorwire.com
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