Wednesday, January 8, 2014

Sage Dynamics Firearms Training: CMC Trigger Review

When it comes to AR triggers, I know what I like; consistency, reliability, simplicity and a short pull with minimal creep and very little reset in a 4-3.5 LB trigger.  I don’t care for two-stage triggers and don’t worship at the mil-spec altar because I learned a long time ago that mil-spec doesn’t always equal the best you can get (and the term gets thrown around very loosely).

Since I know what I like, I already am very happy with my AR triggers since I went through the trial and error of finding what I wanted some time ago. But technology improves, or someone innovates or someone finds a way to do something better or as-good-as for a lower price point (I don’t mind paying for quality, I don’t want to pay for a brand name and quality).  So when I heard a little about CMC triggers, I decided to check them out.  I ordered their straight profile trigger with a 3.5 lbs pull to replace a two-stage Colt trigger that was languishing away in a lower that didn’t get much use.

CMC Flat Profile Trigger
The CMC design is straightforward; a drop-in, self-contained unit that is built without assembly screws or the ability for adjustment (screws, both those for assembly and for adjustment can come loose, not good for consistency).  Being self-contained, it installed easy and once the supplied pins were in, there was zero movement inside my Battle Born lower of the trigger group.  Before taking it to the range, I cycled the trigger a few dozen times to get a feel for the pull and reset and look for any potential issues right off the bat.  It ran like a sewing machine, at least under dry fire conditions.

My evaluation was simple; 1000 rounds as fast as possible without any lubrication, literally running it right out of the package.  I brought along three different uppers and the 1000 rounds was made up of 400 rounds of 55 grain .223 PMC, 400 rounds of 62 grain 5.56 Lake City (green tip) and 200 rounds of 77 grain Black Hills match .223.  I loaded each respective group of ammo in its own group of magazines and just for fun, loaded two magazines with ammunition from all three groups mixed together.

For uppers I used a Loki, Noveske and Aero Precision.  Both the Noveske and Aero Precision use the WMD guns Nickel Boron BCG, the Loki has Loki’s proprietary Nickel Boron BCG. Not that the BCG is critically important for the test of a trigger but I wanted variety and needed multiple uppers since I planned on running the test fast, which would be a lot for one upper to handle (1000 rounds in a short period of time isn’t always the best thing for your barrel).  I also brought along a second lower with a standard DPMS trigger (5.1 LBS pull).

The Uppers
I was running an evaluation on some other gear at the same time, meaning I didn’t want to have to constantly worry about the trigger;  I wanted it to do exactly was it was supposed to, which is make my rifle go bang every time I wanted it to. 

Mission accomplished.

First, the straight profile trigger is perhaps my favorite feature; it helps with consistent finger placement and makes for a very short pull.  As the CMC breaks at 3.5 Lbs (mine breaks at exactly that, though I have heard of some slight +/- divergence, which can be expected), it makes for a very fast trigger.  Very fast.  Using a PACT timer I started testing with the Loki upper.   I recorded an average split of .16 (the best being .14, the worst being a .19) when shooting rapid fire. 

The short pull and short reset obviously help with the split times, as does the light weight and flat profile trigger.  My groupings at 5-10-25 yards were consistent or slightly better than rapid shooting with other triggers.  I used 100 rounds of 55 grain and 62 grain and 50 rounds of 77 grain I didn’t experience any failures to fire or failures to reset.  I repeated the rapid fire test a second and a third time using the Noveske and Aero upper with the same round count with near identical results.  But speed isn’t everything.

10 Rounds at Speed
One of the enemies of accuracy is asymmetrical tension, the trigger pull is a necessary source of tension and the lighter the trigger (within reason) the greater the trigger pull can aid in reducing overall tension on accuracy (if we are doing everything else right).  Can you be accurate with a mil-spec trigger? Of course, you can be accurate with any quality trigger and many shooters can provide practical accuracy with the worst of triggers but that doesn’t mean we shouldn’t want the best trigger we can get for the way we shoot. I increased my testing range to 50-75-100 and 150 yards, shooting on steel with a hit reactive thoracic cavity plate.

From standing to prone I went through 100 rounds of 55 grain and 62 grain, shooting as fast as I could accurately hit. The CMC trigger ran without fail and my split times at 100 and 150 yards were noticeably faster than shooting the same range with a factory “Mil-Spec” trigger I brought along in a second lower. My best time on the “Mil-Spec” was 5 rounds in 2.10 at 100 and 2.34 at 150, the CMC came in at 5 rounds in 1.90 at 100 and 2.22 at 150, all were hits to the thoracic plate, not just “on steel.” These aren’t extreme ranges, and the trigger isn’t the only important component in accuracy but there are appreciable differences between the triggers performance using otherwise nearly identical components.

The remainder of testing was done between rapid and precision pace fire, in multiple body positions and with the rifle fired “off-axis,” or turned on its side to see if the trigger group would drift or rub on the lower, it didn’t. I quickly went through the remainder of the ammunition, including the mixed magazines without any issues with the CMC trigger. 

Is this impressive? It shouldn’t be when it comes to reliability, though it actually is for a self-contained drop in trigger. I have used two different self-contained drop-in triggers (a Timney and a POF) and had reset issues with both and the Timney eventually started binding so bad I removed it and threw it away. 

The CMC does exactly what it is supposed to do, it works and it’s reliable.  Having put 1000 rounds on it in just over an hour of shooting without any service or lubrication and not a single issue, I’m confident in the CMC design.  Granted, the trigger is still young compared to some of my others (I have a Geissele closing in on 10K rounds and a CMMG with match springs that is probably well beyond its recommended service life yet still reliable).

So if you are looking for a light pull competition trigger or an improved trigger for your self-defense rifle, I highly recommend CMC products.

Aaron Cowan is the Lead Instructor for Sage Dynamics, a reality-focused firearms and tactics training company that provides practical instruction from the fundamentals to advanced skills for the civilian, police and military professional.  Aaron served in the US Army as an Infantryman,  as a private security contractor overseas and as a police officer.  In addition to patrol he worked as a a SWAT team member, SWAT deputy team commander, SWAT sniper, sniper section leader and in-service police training officer.  Aaron holds multiple professional certifications including the National Rifle Association Law Enforcement Division’s instructor training program, California POST certified academy instructor, Advanced Law Enforcement Rapid Response Training (ALERRT) Active Shooter Response Instructor and Simunitions Scenario Instructor among others. When he isn't teaching or training, hes writes semi-regular for Recoil (web) and Breach Bang Clear among others."

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