Review
Overview
PRESS RELEASE - Chip McCormick Corp. has recently been issued U.S. Patent #7,162,824,
a patent covering the use of CMC’s drop-in, totally self contained trigger module
for AR-15 style rifles; as well as most other semi-automatic rifles with upper/lower
receiver designs. CMC is also in possession of Patent #D504,168 covering design
of the innovative Flat Trigger for AR-15 style rifles.
Keeping up with demand for the CMC AR-15 trigger modules has been problematic since
introduction. CMC is pleased to announce a substantial investment in new state-of-the-art
production tooling which will not only yield improved quality and consistency, but
will also allow virtually unlimited supply in 2007.
These newest production components have been tested under extreme conditions. The
tests include documented 50,000 round cycle testing with subsequent magnafluxing
for cracks and/or fractures. Then the same parts used in the 50,000 round testing
were frozen to 20 degrees below zero, tested for 500 more cycles and magnafluxed
again for cracks and/or fractures. No cracks, fractures or failures of any kind
were found.
Without compromise to function, reliability or service life; the CMC drop-in, totally
self contained trigger modules for AR-15 style rifles, reduce gunsmithing and installation
time for obtaining a match grade trigger pull to a matter of minutes; including
safe and proper function verification. Although these products are designed to significantly
reduce the investment of time, effort and cost previously associated with obtaining
a reliable match grade trigger pull, CMC must still recommend that any modifications
associated with safe and reliable function of the trigger mechanism be implemented
by experienced professional gunsmiths.
CMC’s AR-15 trigger modules are designed to fit any Mil-Spec receivers except Colt
brand receivers with sear blocks, and are available for small or large pin receivers.
Each AR-15 trigger module is backed by a “Satisfaction Is Guaranteed*” offer.
Description
Design Ojectives & Technical Information
- Combat Reliability & Service Life
- Match Grade Quality & Trigger Pull
- No Compromises In Function Or Usage
- To Be Compatible With Mil-Spec Lower Receivers
Combat Reliability & Service Life
Over twenty years ago the founder and original commander of the US Army's most elite
unit became a best friend and close ally of Chip McCormick Corp. (CMC) president
and founder, Chip McCormick. Through all the knowledge, experience and combat stories
that man shared, a very clear understanding of what enhanced performance with reliability
is and its importance. When it was time to take the concept of the drop-in AR15
trigger module, used under US Pat. 7,162,824, from the drawing board and into production
all the knowledge and experience gained from that man was considered as a primary
area of focus for the CMC AR15 trigger modules. That is why the new generation II
of CMC drop-in AR15 trigger modules incorporate the following features:
Same Reliability and Service Life as Traditional AR15 Triggers
The most important features of the CMC trigger group is the fact that the primary
design objectives and resulting functions are made to be enhancements to the original
design of the traditional AR15 trigger group, and specifically not to be compromises.
However, the dynamics of the trigger pull itself is on par with what is commonly
known as “match grade.” The module box that contains the CMC trigger group is designed
to keep side to side wall thickness as close to standard as possible. This means
that if build ups of grease, grime, sand, powder residue, etc. occur the internal
parts still have the clearances to continue to function as the factory standard
designs would function under these conditions. Had the internal geometry been closed
in around the moving parts to center and/or contain the internal parts it wouldn't
take much to contaminate the parts, lose clearances and result in malfunctions.
The stainless steel sheet metal module is a very high tech, close tolerance, and
critical component with +/- .001” tolerances in areas critical to function. A very
high quality component that is not easy or cheap to make.
- There are no screws in this design – No matter what methods are used to secure them,
screws can and will come loose and we have done everything possible to avoid Murphy's
laws. And we all know that when Murphy's laws strike, they will normally occur at
the worst possible times. So not only would the use of screws for attaching the
trigger module to the receiver or to lock some part in place offer no benefit, they
would be very counterproductive to the design objectives. Nor would screws secured
with adhesives add to the effectiveness of the mechanism. The CMC design purposely
does not rely on any screws or adhesives that could in any way could allow some
part to loosen and cause a failure.
- There is no adjustability in this design – As that old friend warned, if some well
meaning, unqualified human can tamper with a perfectly functioning mechanism, they
will. Can't allow that for people who put a premium on reliability and the huge
majority who understand the disadvantages wouldn't tolerate it anyway. Adjustability
means an additional part or parts would have to move in addition to the components
that absolutely must have movement. Clearly adjustable features would offer no benefit
to reliability, but could definitely compromise reliability. Furthermore, do to
the nature of the design adjustability is not necessary.
Why is adjustability not necessary? The only valid reason we can see that adjustability
would serve any purpose toward reliability in an AR15 rifles is to ease and reduce
the time during the installation of the old style trigger groups, where you begin
with a bunch of loose parts. You see, the fact is, every different brand of AR15
rifle receiver is more than likely built to a different set of nominal dimensions
and tolerances, even when based on military specifications. To add to the problem,
many AR15 rifles are reverse engineered with out any reference to the military prints.
To make a precision set of individual parts to one recipe (the same geometry for
every respective part) that would function reliably in every different brand of
AR15 is clearly and obviously unlikely. This is surely why we don't see a complete
set of individual parts that will drop-in, without any fitting required, being offered
for sale.
So if you ignore the reliability factor and Murphy's laws, adjustability in a in
a loose set of trigger group parts might be useful. But obviously, to maximize reliability
its best to have a set of non-adjustable trigger group parts installed by a qualified,
experienced gunsmith who can fit, file, hone, check for safe and proper function,
and then keep that group of trigger parts dedicated to the rifle they were fit to,
exclusively.
- Consistency Is Critical To Reliability – Who is a qualified AR15 trigger group gunsmith
And who isn't? How do you determine who is and who isn't? Leaving the answers to
those questions up to the so called “experts,” with the CMC drop-in AR15 trigger
you are buying consistency that narrows the only remaining proficient gunsmithing
questions down to what AR15 gunsmith is qualified to insert two pins and proficiently
determine the results have yielded safe and proper function. If you want to take
any given trigger module out of one rifle and move it into another, and then again
to another rifle, and so on, the same level of AR15 gunsmithing proficiency apply;
who can proficiently insert two pins and determine the results have yielded safe
and proper function. The lower receiver has to be pretty far outside of the military
specification geometry for the CMC drop-in AR15 trigger module not to fit and/or
yield safe and proper function.
Match Grade Quality & Trigger Pull
CMC's founder and president, Chip McCormick, got his start in the firearms industry
as a professional sponsored combat shooter with a career that spanned 9 years. In
that profession he shot pistols, shotguns and rifles. No one wins World Championships
or any other world class event if their firearms don't have the very best triggers.
The necessary elements are experience, knowledge, state-of-the-art design, testing,
very close tolerances, precision manufacturing and quality control. After years
of producing and improving processes, and geometry; the newest generation II of
CMC drop-in AR15 trigger modules have brought every element of what yields Match
Grade quality up to the highest levels.
Trigger Pull Dynamics
A clean, crisp trigger release and 3.5 pound nominal pull weight. Key elements to
any trigger group that allows the shooter's performance to meet the potential of
the firearms. CMC's drop-in AR15 trigger modules are factory set to a nominal trigger
pull weight of 3.5 pounds. To most people, a truly clean, crisp breaking trigger
pull set at 3.5 lbs. seems much lighter. If you know anything about the outstanding
marksmanship demonstrated at the Camp Perry Championships by shooters using a minimum
4.5 lb. trigger then you will not have any doubts about what is possible with a
3.5lb trigger pull. Can CMC set the drop-in AR15 trigger modules at 4.5lbs or more?
Yes, we have been doing so for law enforcement and military orders for some time
now. If you order direct from CMC and request 4.5lbs for your trigger we can do
so for you, too. We will not set the trigger modules to lighter pull weights.
Over-Travel & Take-up
These elements are critical to the overall performance of a world class shooter,
but are also important to any shooter who wants to demonstrate precision shooting.
Unlike traditional AR15 trigger groups one of the most spectacular elements of the
CMC AR15 drop-in trigger modules is that match grade over-travel and take-up can
be accomplished with geometry and without the need for screws or other moving parts.
Sure, some people have different preferences, but due to the many years CMC's trigger
modules have been in production and the many thousands sold, customer feed back
has made us very confident that the design of these products is such that take-up
and over-travel is right in the sweet spot for both. And it wont change because
its done with geometry on not moving parts that can come loose (usually at the worst
time).
- Every component of the CMC drop-in trigger modules maintain tolerances of +/- .001”
(one thousandths of an inch) or less wherever two critical surfaces engage or interface.
The same tolerances apply to each and every hole location.
- Surface finish is critical for obtaining that magic “feel” that is absolutely necessary
with a Match Grade Quality trigger group. Its not easy and takes of a lot of time
to develop an effective, precision tooling set up for producing mirror finishes
on the components with critical surfaces as are incorporated in the CMC trigger
modules.
Construction
No Compromises
How important is reliability to you? CMC's drop-in AR15 trigger modules get their
outstanding combat reliability and service life, and match grade quality & trigger
pull without compromises like reduced sear/hammer engagement or using reduced power
springs. The cheap, easy ways to reduce trigger pull weights are by minimal sear/hammer
engagement and reducing spring rates on the trigger return spring, and the hammer
spring.
But CMC's way of thinking is that the cheap, easy methods are very counter productive
to the objectives for this design. For one, reduced spring forces increase lock
time (the time from when the trigger releases the hammer until the hammer strikes
the firing pin) which reduces accuracy potential. Second, reduced spring forces
can cause trigger groups to fail much easier in grimy, dusty and/or fouled conditions.
Third, reduced spring force on the hammer causes light strikes of the firing pin
on the cartridge primer. The potential for light strikes has two problems that are
especially concerning in AR15s; failure to discharge the round is the obvious problem,
but also, if the rifle is fired a lot without cleaning (especially in nasty environments)
fouling can cause light strikes to occur long before they would have with full power
springs.
Also, for those of us that like to go to the range and practice or shoot a lot its
nice to be able to reliably use inexpensive military surplus ammunition; which can
be done with the CMC trigger groups. However, for those of us that also like to
do serious precision shooting with high quality ammunition its nice to know that
you have a great match grade trigger pull that facilitates precision with very fast
lock time. What are the benefits of settling for less?
Engagement
The amount of engage of the sear tip to the hammer cock notch is extremely critical
for reliable function under varying conditions. The cheap and easy way to obtain
reduced trigger pull weights is by reducing engagement to bare minimums. Maybe that's
OK for bench rest rifles, match only rifles or rifles that are always kept clean
and carefully handled, and reliability is not of grave concerns. However, the CMC
drop-in AR15 trigger modules are designed to be well suited to all aforementioned
usages without any compromises to reliability under all conditions of usage.
Springs
Another one of the cheap and easy ways to obtain reduced trigger pull weights is
with reduced power springs. The springs used in CMC's drop-in AR15 trigger modules
are custom made using the finest music wire spring materials available and are spec'd
out to replicate the forces of the springs used in military weapons. This means
reliable discharge with inexpensive military surplus ammo, faster hammer lock time
to maximize accuracy, and longer lasting reliability in various environments.
Surface Finishing
This was discussed previously, but the subject also belongs in this area. Reducing
sear/hammer engagement and reducing spring forces to allow for lighter trigger pull
weights both reduce the requirements for superior surface finishing on engagement
surfaces. With the full force springs like CMC uses; lighter, crisp, clean trigger
pull is unobtainable without extremely smooth, consistent, highly polished surface
finishes on all engagement surfaces. Its not the cheap, easy way, but its the best
way from CMC's point of view.
Materials
CMC uses only the highest grade materials and manufacturing processes available.
Each one, the newest materials we are incorporating, the heat treating specifications
and some unique and additional processes not used before in these applications,
are the results of intensive studies by a team of highly qualified engineers. No,
we wont say exactly what makes all these elements proprietary or others would surely
copy us as they have in the past. But we will tell you this:
Extreme Torture Testing
To validate the findings of the engineering of the new generation II trigger modules,
CMC implemented extreme torture testing. The tests include documented 50,000 round
cycle testing with subsequent magnafluxing for cracks and/or fractures. Then the
same parts used in the 50,000 round testing were frozen to 20 degrees below zero,
tested for 500 more cycles and magnafluxed again for cracks and/or fractures. No
cracks, fractures or failures of any kind were found.
Compatibility
Which AR15 Rifles Are Compatible
The CMC drop-in AR15 trigger modules are designed to fit any lower receiver manufactured
to be within the standard military specifications for nominal dimensions and tolerances,
except Colts ® with sear blocks. CMC does offer models of the drop-in AR15 trigger
modules that will fit Colt ® brand rifles with larger (.173” diameter) than standard
retaining pin diameters. It's always recommended to have an experienced and qualified
AR15 gunsmith to be the one to qualify safe and proper function of the trigger module.
What's Included
The CMC Trigger Group is shipped with the following:
- Instruction Card
- Trigger Group Assembly
- Two pins
- Several Clips to prevent pins from working lose
Features
- Easy Install
- patented one-piece assembly installs in minutes. Insert the one piece assembly,
install the supplied over-sized pins, check for safe and proper function and you're
done.
- Precision Made
- Tolerances of +/- .001" for all engagement surfaces. Hammer, trigger, disconnector
and pins are made with the highest grade, hardest, longest wearing materials available.
Full-strength music wire springs for fast lock time and reliable discharge. The
assembly is contained in a hihg-grade 410 stainless steel housing.
- Factory Tuned
- For better than average match-grade trigger pull with minimum take-up and over-travel.
- Options
- Available in single or two-stage trigger actions for small or large center pin receiver
holes.
WARRANTY
Chip McCormick Corp will refund the purchase price of any unaltered drop-in AR15
trigger module within 30 days of purchase. Offer applies to purchases direct from
CMC or participating dealers only. Products returned from dealers to CMC for credit
must include proof of the customers purchase. Refund offer does not include cost
of shipping, handling, or other ancillary charges. Participating dealers are responsible
for refunding their customers. CMC will be responsible for refunding the CMC dealer
upon receipt of the returned products.
