The FCU X01 came out six years ago. It has been eclipsed by other chassis systems like the Flux Raider but Exo Gunner is making FCU upgrades for it along with some other upgrades for other guns. All thanks to the benefit of 3D CAD and printing.

More FCU @ TFB:

• TFB REVIEW: Fire Control Unit X01 PDW – The Future Of Small Arms
• Coming Soon: The Fire Control Unit X03 Chassis in Action
• TFB Review: MP-57 Chassis By Custom Smith MFG

FCU Upgrades For The X01

Photo by Exo Gunner

One of the more popular accessories for small pistol chassis is to have a spare mag holder/grip. Exo Gunner has designed one as part of his FCU upgrades. It probably attaches via the M-LOK slot in the chassis. It is available now via his Instagram for $59.

Something FCU had planned but we never saw it, was a muzzle blast diverter for the X01. Well, Exo Gunner has made one as part of their FCU upgrades. It is for compact slides with threaded barrels. It is called the Pulsar. It has a blast diverter that is held in place with the side panels you see in the photo below. Those are attached to the thumb rests which are bolted on from the outside.

Photo by Exo Gunner

Photo by Exo Gunner

You can see how far back the slide and muzzle of the barrel would be in the X01. But now you have a blast diverter so the hot gasses don’t escape inside the chassis.

Photo by Exo Gunner

As far as FCU upgrades, the Pulsar seems very practical. It will help keep hot gasses from escaping inside the chassis and redirect it out the front. It is unclear if the Pulsar blast diverter is threaded onto the barrel. Considering how it is keyed into place with the thumb rests, I imagine it would hinder the tilting barrel if it was threaded on. I have reached out to Exo Gunner for clarification and waiting for his response.

MP57 2.0

Here is something a little different for FCU upgrades. If you recall, the Ruger-5.7 has a fire control unit somewhat similar to the SIG P320. It was Custom Smith Manufacturing (CSM) that made a chassis for it. Well, Exo Gunner has made FCU upgrades for the Ruger-5.7 as well. His chassis is similar to the CSM but upgraded. Right away it appears the chassis has two M-LOK slots on the side. What is more interesting are the spare magazine holders.

Look at the striped chassis below. It seems there is an angled mag holder for use in the front of the chassis and a straight one at the rear as a cheek rest.

Exo Gunner has even designed a rear grip module for a Glock handgun. It seems inspired by the Strike Industries Modular Chassis (SMC) but rather than a chassis, it is a beaver tail grip panel. It looks to use the same optics bridge as the SMC and has a Picatinny rail at the back for use with the Strike Industries dual folding adapter.

Here is the same grip module with an SB Tactical collapsing MPX brace.

For more information, check out Exo Gunner’s Instagram page.