Review: Echo Nine Three CAV-15 MKII Modification Package

I’ll start this review with a bit of a history lesson. Joe Elledge of EchoNineThree (E93) was one of the few factory trained armorers qualified to work on the CAV-15 MKII lower receivers back in the days when they were still being made by Cavalry Arms. Apart from his standard armorer work on the lowers, he developed a set of modifications for the lowers that dealt with some of the perceived shortcomings and adapted it to more modern techniques.

E93 CAV-15 Modifications

Before you say anything… yes, I know the front sight is backwards. It works better as a thumb stop this way.

The modifications included shortening the buttstock, stippling the grip, and undercutting the trigger guard as well as adding a sling mount of his own design. The modifications were so well executed and well-liked by Cavalry Arms that they allowed the mods to be completed under warranty! Many of these features were to be included on the MKIII version of the CAV-15. However, setting up production of new receivers is expensive and the well-publicized drama between Cavalry Arms and the BATFE took place before the MKIII receivers could become a reality.

Now that GWACS Armory has taken over production of the CAV-15 MKII receivers, E93 is once again accepting lowers for modifications. I recently had the chance to review a GWACS Armory CAV-15 MKII and came away surprised at how much I liked it. I probably wouldn’t have considered using an all polymer lower receiver before, but these are a very viable option, especially for specific applications. I was especially intrigued to see if E93’s mods would bring any additional functionality to the table.


E93 completed separate modifications to my receiver: the stock was shortened to approximate length of a collapsible stock in the second position out from the receiver (this includes fitting a new buttplate), the trigger guard was undercut to allow higher hand placement, the grip was stippled to offer a more aggressive grip, and a sling mount was added toward the front of the stock in the typical single-point sling mounting location.

My sling mount is a prototype and I do not have pricing information at this time but the rest of the package runs only $125 from E93 (or $85 to shorten the stock and fit the new buttplate). I think that is extremely reasonable given the quality of the work and when you consider what a new grip and stock might cost with a standard receiver.

E93 CAV-15 Modifications Sling Mount

Observations from Use

I looked over the work when I first received the lower back from E93. The stock is cut cleanly and evenly. The new Pachmayr buttplate was fit well to the receiver. The undercut is executed very cleanly and evenly as well. The stippling is well executed with no voids or gouges. The stippled areas did show some slight discoloration but E93 told me this would happen and I know from my own stippling work that this will happen with lighter colored plastics. It was very minor and you would be hard pressed to even notice it now that the grip is dirtied from spending lots of time in my grubby mitts.

I tested the lower with a variety of different upper receivers. It spent most of its time mated with a Spike’s Tactical GMP upper. I liked this combination so much that it will likely stay this way as an iron sights only carbine. I also tested it with my lightest weight upper, a BCM 14.5” lightweight profile mid-length with a 13” Troy Alpha rail. The combination came in at just 6.65 pounds. That is impressive considering that this isn’t some stripped down lightweight build, this includes a free float rail, back up irons, Aimpoint, sling, hand stop and light! The E93 modified CAV-15 MKII lower shaved about 3/10ths of a pound versus a standard lower with collapsible stock!

The biggest and most noticeable functional change comes from the shortened stock. Joe was able to shorten the stock to the length of a collapsible stock in the second position which is where I normally keep my collapsible stocks. This shorter stock position works better for me when I square my upper body to the target and it is short enough that it works well with body armor.

E93 CAV-15 Modifications Stippling

The new rubber buttplate does a good job of locking the stock into my shoulder. It is still removable though not as easily as the original buttplate since the screws that fasten it to the receiver are buried in the rubber. I rarely, if ever, remove the buttplate so this is a non-issue for me.

The stippling has a fairly aggressive texture. It offers great grip without being too harsh on bare hands. It also works very well with gloves. The undercut trigger guard is a really nice touch. It makes it easier and more comfortable to get a higher grip.

The sling mount is very simple and I mean that as a compliment. Its simplicity makes it very versatile. It is a hook type sling mount that is bolted to a steel backing plate inside the stock. The mount is Melonite treated for corrosion and wear resistance. It can accept snap hooks or MASH hooks. I have a Blue Force Gear UWL attached to mine and it makes for a very nice combination. The location of the mount allows it to be used with either single or 2 point slings. This E93 sling mount is a vast improvement in both location and usefulness to the factory sling mounting point.

E93 CAV-15 Modifications Undercut Trigger Guard

The undercutting of the trigger guard is well executed. The beveled edges of the undercut make the grip more comfortable.

Wrap Up

These mods greatly improve how well the CAV-15 MKII works for me and the way I shoot. The quality of the work is great. The improvements are very functional. I am not sure what else I can say other than I consider the E93 mods to the CAV-15 MKII to be money well spent.

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NOTE: Due to a recent fire at the E93 machine shop, gunsmith services have been suspended temporarily.

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One Response to Review: Echo Nine Three CAV-15 MKII Modification Package

  1. Rick Frazier January 5, 2014 at 21:17 #

    I use the Magpul Rail sling attaching loop to make a single point bungee hook-up.

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