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. Foxtrot Mike's ISU-9 upper receiver is an attempt to solve that at the root, and in this article we’ll try to explain how it works. The barrel carries 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.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.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. Both forward-charging and a traditional mil-spec AR charging handle are supported. There is a transferable lifetime warranty, and it will be sold through Foxtrot Mike, Primary Arms and Silencer Shop.The price is the headline nobody expected. Integrally suppressed uppers normally sit well into four figures, but the ISU-9 has an MSRP of $499. CEO Paul Noonan frames that as the whole point, calling it advanced technology at a price everyday Americans can afford. If the gas system works as described, this is one of the cheapest routes into a genuinely quiet carbine that exists.Note that this is an upper part only. The release does not say which lowers it works with or whether buffer requirements change.Foxtrot Mike ISU-9 the details:Integrally suppressed 9mm upper receiver, built on the VFM-9 platformPatented barrel-porting and gas-management system, eight years in developmentPorts intersect the lands of the rifling to preserve accuracyUses suppressor back pressure to help drive the action, reducing reciprocating massBrings conventional 115 gr, 124 gr and heavier 9mm to subsonic velocityUltra-slim handguard with 28 full-size M-LOK slotsM-LOK hardware installs without removing the handguard or suppressorForward-charging and mil-spec AR charging handle compatibleTransferable lifetime warrantyMSRP $499, sold through Foxtrot Mike, Primary Arms and Silencer ShopI could not find any more details or images on Foxtrot Mike’s homepage, Facebook or Instagram, but I’m sure it will show up in due time. https://fm-products.com/ For you, does an integrally suppressed upper appeal more than a threaded barrel and a separate can?If this post has you ready to hit the range, head over to gunranges.com - a free directory to help you find shooting ranges near you, wherever you are in the United States.