CORE 15 Rifle System
by Jeff W. Zimba

Early in 2009 when it was very difficult to simply pick up the phone or punch in a URL to order black rifles and accessories, the CORE 15 was conceived. With the limited availability combined with ideas to improve the platform, the decision to go ahead with the old adage, “If you think you can do a better job, go ahead and do it yourself.” is exactly what they did and have never looked back.

Not wanting to be another entry-level or “plinking type” black rifle builder, the CORE 15 team set out to develop their own unique identity. They would decide to offer both Direct Gas Impingement (DGI) guns and Piston guns, and after studying several platforms they determined that the Adam’s Arms piston system would be the one they would adopt.

Even though the CORE 15 rifles have some unique features, their signature in the black rifle market would not be limited to one style but to a company creed that whatever firearms were already available elsewhere in the industry, they would strive to make theirs better. Manufacturing as many parts in-house as possible, with the list growing all the time, would give them more flexibility in their quality control. Building guns to tighter tolerances striving for quality over quantity would become their goal and remains so today. CORE 15 rifles are manufactured with an emphasis on quality in all areas from fit to finish with the flexibility to meet the requirements of any end user.

Let’s get Technical

The rifles sent to Small Arms Review for evaluation included 3 different models. The MOE DI, the TAC Piston and the MOE Mid-Length. The Mid-Length was built on their Hardcore lower receiver and also used a piston system. An interesting note on the piston guns is their unique attention to accuracy concerns; something often claimed either non-existent or lacking by many fans of the time-proven DGI guns. While the DGI guns are barreled with a 1 in 9 twist, 6-groove button rifled version, the piston guns employ a 3-groove 1 in 8 twist polygonal match barrel.

The piston operating system has three gas settings. There is a standard “Open” setting for normal use, a “Restricted” setting for use with a sound suppressor and a “Closed” setting for use when hand-cycling is desirable for optimum sound reduction. The adjustments are made with no tools necessary, by simply depressing a spring-loaded button and rotating the gas plug to the desired setting.

CORE 15 receivers are manufactured from Mil-Spec hammer forged 7075-T6 aluminum and finished with a Mil-Spec Type III hard-coat anodized finish. A 6-position commercial buffer tube is used on all rifles unless ordered with the Magpul UBR stock. DGI guns employ a Mil-Spec 304 stainless steel gas tube and a pressure tested 8620 steel bolt carrier and bolt carrier key, chrome lined internally. The bolt is magnetic particle inspected. The piston guns are supplied with a proprietary monolithic bolt carrier (also MP and pressure tested) and bolt. All rifles are shipped with an A2 flash hider and a Dry-Lube internal finish.

All supplied sights were Magpul MBUS flip-up open sights. They are rear sight adjustable for windage and the front post is adjustable for elevation with normal sight tools. While these sights are not an expensive sight or usually used in “match” environments they work well and produce good groups.

With a focus on quality and durability, you will find a heavy Magpul presence on all these guns as an option. All rifles are shipped from the factory with Magpul P-Mags regardless of the configuration and a full line of Magpul furniture and accessories are available when ordering your CORE 15 rifle system or added as an accessory at a later date.


The Mid-length piston rifle submitted for testing had a unique feature that was obvious the second it came out of the box. It was built on the CORE 15 “Hard Core” lower receiver. This receiver has a unique mag-well that is shorter than a standard mag-well and very heavily beveled. It was primarily designed for 3-gun match shooting where reload speed can make the difference between first place and not placing at all. Although we are certain it is effective in these match circumstances, there are numerous operators and end users who are just as concerned with increasing the speed of changing magazines and will also find this unique design change attractive.

Less Talk, More Shooting

All testing was conducted at the Small Arms Research Test Facility in Fairfield, ME. A hot, sunny afternoon was made bearable with the use of a 10’x10’ popup and the determined range was 50 yards from the impact area since the testing was for both function and practical accuracy with open sights.

The first test was a simple function check. Numerous magazine types and a mixed batch of ammo is a common test we use to check for functionality. All of the test rifles passed with high marks in this phase of testing. The only firearm related malfunction we noticed in several hundred rounds were a few failures to feed upon the chambering during rapid-fire exercises with one particular rifle. When the CORE Group was contacted to ask about this condition we were notified that these guns are built to extremely tight tolerances, especially the bore of the upper receiver and a short “break-in” may be more desirable than an “out of the box hammer session.” As any well-tuned and assembled firearm, these guns are built more with accuracy as a primary consideration rather than a gun on the loose end of the tolerance scale, for “spray and pray” play. We were also informed that more parts were being built in-house now to provide matched parts with exacting tolerances rather than relying on any of the numerous Mil-Spec parts that may fall on any side of the spectrum. After a few more rounds and a proper cleaning, the problems we encountered were evidently resolved as this gun has not failed to function in any way in our subsequent trips to the range. We moved on to practical accuracy testing.

Armed with several Magpul P-mags and an assortment of ammo, a basic sight-in was completed with each rifle. The ammo was all separated and we settled on WPA (Wolf Performance Ammunition) 55Gr FMJ ammo for the rest of the session for continuity. On this particular range session we had 2 test shooters. One had cracked a few ribs about 30 minutes before the testing started so we were not sure about the level of performance but we moved ahead anyway. 10-shot groups were the protocol during these tests.

The first rifle out was the MOE M4 model. It is a very lightweight platform at only 5.9 pounds and well balanced. The Magpul MOE stock, grip forearm are quite comfortable and this combination has been well received by all who have handled it. It is a “flat-top” upper receiver, as are all the CORE 15 rifles so the mounting options are quite broad. As mentioned earlier we used the provided Magpul open sights.

This writer was the first to shoot a group. The target was a standard, full size law enforcement training target with a few 3” orange dots placed on the paper for a more consistent point of aim. The spotter was mumbling with pleasure during the first group and when it was over the first words out were “You ruined his day!” Cracked ribs and all, 8 holes were very close in the orange with the other 2 rounds cutting the same hole just outside the orange. Shooters swapped positions as the spotter became the shooter and vice versa. This was the protocol throughout the day. The second group was equally impressive, maybe even tighter.

The second rifle fired was the CORE 15 TAC Piston followed by the MOE Mid-Length on the Hardcore Lower receiver. All three rifles performed with similar accuracy. Nice groups in a shadowy impact area due to the position of the sun in the early afternoon. For open sights and firing as fast as the next target acquisition was made, we were pleased and impressed with the accuracy.


While Small Arms Review tested only three different CORE 15 rifles, they are available in numerous lengths, styles and configurations: from 20-inch rifle length to carbine length and even mid-length, in DGI or a Piston operating system. They are available in a many Title I or Title II NFA configurations for agencies or qualified individuals including Short Barreled Rifles (SBR) or Post-86 machine guns available to agencies or Class III dealers with demonstration letters. If complete guns are not necessary or desired, individually and matched upper and lower receivers are available for self-builds as well as their piston system upgrade and all accessories, including several brands of sound suppressors. Anything found on their complete rifles can be purchased as accessory at any time. The rifles were indeed unique with a good feel. Their “Hardcore” lower receiver is innovative and will be very desirable to those more interested in competition or just for those looking for something different. There are numerous, more subtle differences the closer you look, like the CORE 15 oversized trigger guards. These are not only attractive and unique but there are at least 3 different designs and they are helpful when shooting with gloves. Since the MSRP is varied greatly on the rifles we tested and it is based on the accessories ordered, we think you will find it more useful to check their website for specific information.

With their recent addition of Israel (Izzy) Anzaldua to the CORE 15 team as reported in a previous issue of Small Arms Review, we are certain that the innovation we already see will be magnified several times and we are anxious to watch for any future offerings. We are also excited about some long term testing to provide a much more detailed report with many more variables than an initial T&E project will allow.


CORE 15 Rifles & Accessories
4600 West Highway 326
Ocala, FL 34482
Tel: (352) 401-9070
Fax: (352) 401-9667
Email: Sales@Core15rifles.com
Website: www.Core15.com

Wolf Performance Ammunition (WPA)
P.O. Box 757
Placentia, CA 92871
Tel: (800) 757-9653
Fax: (714) 632-9232
Website: www.Wolfammo.com

This article first appeared in Small Arms Review V15N3 (December 2011)
and was posted online on November 1, 2011


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