Concussion Altering Gas Expansion Device for your 7.62 Platform

Bolt-on devices to direct lateral gas expansion from muzzle brakes really took the shooting world by storm about a year and a half ago or so, and I’ve checked out a few of them ranging from the Ferfrans CRD to Fortis Manufacturing’s CONTROL. Most directional gas expansion devices are a cylindrical sheath that attaches directly to the muzzle device and are purported to direct rapidly expanding lateral gas expulsion forward towards the muzzle after the brake/comp does its job.

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My experiences with the ones I’ve sampled have been pleasing and work as advertised, however, all of them are pretty brake-specific based on manufacturer design.

The team at VG6 Precision released their Concussion Altering Gas Expansion (CAGE) Device last year for the 5.56 platform, and I have one mounted on my go-to Santan Tactical 14.5" build that is my favorite personal AR in my stable.

The CAGE differs drastically from its competitors in that it is not a cone, rather, it is a very streamlined sleeve that bolts directly onto VG6 muzzle devices such as the GAMMA and EPSILON by way of a shim and two set screws. It is not mounted with a quick-attach system, but affixed as a more permanent, but ultimately removable add-on to augment the capabilities of their existing brakes.

The C.A.G.E. comes packaged with the C.A.G.E. device itself, a small, grooved aluminum shim, and two set screws. To mount the C.A.G.E. on your VG6 muzzle device, first fit the shim into the grooves on the muzzle device. Orient the shim to the 12 o’clock position, and slide the C.A.G.E. over the shim itself. Orient the C.A.G.E. onto the muzzle device, and lock it down onto the muzzle device by tightening the two provided set screws. That’s it.

The C.A.G.E. is covered in mini-ports that are reminiscent of a cheese grater; the mini ports cover the large brake channels on the GAMMA and EPSILON, creating multiple mini vent points to slow the lateral gas pattern down, reducing the felt side concussion, but not so much as to drastically diminish or ruin the effect of the brake itself.

In my evaluation of the 5.56 version, I found that the design worked well, but there was a slight increase in felt recoil, but not muzzle rise. It does not completely eliminate the discomfort of standing next to a muzzle brake entirely, but the disorienting effects are substantially reduced enough for me to believe that they are worth consideration.

Recently, VG6 Precision released its AK version of the EPSILON, which is a predictably solid brake/FH combo, with a 14×1.0 LH thread, designed for 7.62×39, and comes with an indexing pin slot for traditional AK muzzle device retention. The AK EPSILON I have is currently mounted on my "Beastie" AK project from a couple years ago, and it performs very well. Like the 5.56 EPSILON, lateral gas expulsion is significant, and not something one would voluntarily stand next to for an extended period of time.

Once the CAGE is affixed, standing next to my Beastie while firing was not nearly as bad as with the AK EPSILON unsheathed, so, like its 556 little brother, the AK EPSILON/C.A.G.E. combo also works as advertised.

The AK EPSILON logs in with a suggested MSRP of $94.99, which is not on the inexpensive side as far as high performance muzzle brakes go, but in my experience over the past 2 years with VG6 Precision, it’s worth the retail price.

The C.A.G.E. logs in with a suggested MSRP of $84.99, which rings in at about $180 for the C.A.G.E. and a muzzle device of choice – also not on the inexpensive side to say the least. However since it fits both the 556 line and AK Epsilon as well, there definitely is an added benefit of purchasing the C.A.G.E. for your gas expansion and management needs as you can swap it between all existing VG6 Precision muzzle devices currently on the market.

Want to know more about VG6 Precision? Check them out at vg6precision.com, Facebook, and Instagram.

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* The views and opinions expressed on this web site are solely those of the original authors and contributors. These views and opinions do not necessarily represent those of Guns & Tactics Magazine,
the administrative staff, and/or any/all contributors to this site.

Chris Tran is a police officer for a large municipality in the Pacific Northwest. He writes equipment reviews aimed towards the everyday user with a focus on functionality, durability, and cost effectiveness.

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