BANG, SWITCH, BOO­GIE

A NEW AP­PROACH TO SEND­ING ROUNDS DOWN RANGE

Tactical World - - Contents - By Gor­don Meehl

A new ap­proach to send­ing rounds down the range.

To say that tac­ti­cal shoot­ers are pas­sion­ate about their ri­fles is a gross un­der­state­ment. That pas­sion goes be­yond the rifle as a whole and ex­tends to each in­di­vid­ual shooter’s choices of com­po­nents. Various de­bates rage on: Which is bet­ter, pis­ton or di­rect im­pinge­ment? Is it called a si­lencer or sup­pres­sor? Which is es­sen­tial, a flash hider or a muz­zle brake? The list goes on. One such per­pet­ual de­bate is what type of trig­ger – a sin­gle-stage or twostage – to use to make your AR send rocks down range.

The trig­ger is the shooter’s only di­rect con­nec­tion to get­ting rounds on tar­get. As such, the choice of what your nose picker uses to make the rifle go bang is a very per­sonal one. With the grow­ing num­ber of companies putting trig­gers on the shelves, there’s one that’s of­fer­ing a par­tic­u­larly dif­fer­ent take on the de­sign Mr. Stoner first dropped in to his in­dus­try-chang­ing rifle: Trig­gertech.

Trig­ger De­sign 101

Be­fore get­ting into how the Mis­sis­sauga, Ont.-based com­pany is re­work­ing physics into an up­graded trig­ger de­sign, let’s re­view the ba­sics of AR trig­ger de­sign.

At its most ba­sic, the trig­ger is a lever that pro­vides the me­chan­i­cal ad­van­tage to over­come a great amount of fric­tion to re­lease the ham­mer and make your boom stick go boom. The ac­tual se­quence of events and physics re­sult­ing from a squeeze of the trig­ger are a more de­tailed in­ter­play of various com­po­nents, but for our pur­poses and al­lot­ted space, we’ll keep the physics to a min­i­mum.

Sin­gle-stage trig­gers are the most com­mon type found on off-ther­ack ARS and ri­fles. In one sin­gle move­ment, hence “sin­gle stage,” the ham­mer (or striker) is re­leased. Pulling a sin­gle-stage trig­ger starts the sear mov­ing im­me­di­ately un­til the ham­mer is re­leased with a pos­i­tive crisp break. Since the sear is in mo­tion from the get-go, there’s lit­tle wasted move­ment, gen­er­ally lit­tle take and a short re­set.

“THE TRIG­GER IS THE SHOOTER’S ONLY DI­RECT CON­NEC­TION TO GET­TING ROUNDS ON TAR­GET.”

A sin­gle-stage trig­ger is very ef­fi­cient when shoot­ing fast and in sit­u­a­tions when speed is a prime con­cern.

Two-stage trig­gers have, you guessed it, two move­ments. The first lighter move­ment brings the trig­ger to the no­tice­able wall. Af­ter this “break wall,” the trig­ger func­tions much like a sin­gle-stage trig­ger, ap­ply­ing con­sis­tent pres­sure un­til the sear break and the ham­mer ro­tates forward and bang, rounds go down range. The first stage lets the shooter know when the ham­mer is about to be re­leased. Know­ing when you are about to break a shot is crit­i­cal feed­back when shoot­ing for pre­ci­sion and when shot tim­ing is crit­i­cal.

An­other ad­van­tage of a two-stage trig­ger is in its in­her­ent safety. When in the fire po­si­tion, it’s less likely to have an ac­ci­den­tal or neg­li­gent dis­charge when there’s an ex­tra step in­volved in break­ing a shot. How­ever, be­cause of the ini­tial take up of the first stage and a longer re­set, a twostage trig­ger, in the­ory, is slower than a sin­gle stage. The pop­u­lar­ity of twostage groups is in­creas­ing, even in the speed-shoot­ing crowd.

Trig­ger and Sear

Those are the high-level dif­fer­ences be­tween sin­gle-stage and two-stage trig­gers. But, like I said above, it’s a lit­tle sim­plis­tic to say that you merely pull the trig­ger, the ham­mer drops and the gun goes bang. Let’s dig down a level and talk about the re­la­tion­ship be­tween the trig­ger and sear when break­ing a shot, and what hap­pens to that re­la­tion­ship as we ad­just for trig­ger pull length (not to be con­fused with length of pull), and pull weight. Both weight and pull length af­fect the amount of fric­tion be­tween the trig­ger and sear. If you look at a stan­dard trig­ger group, you’ll no­tice that the sear and ham­mer over­lap. Springs within the assem­bly ap­ply a tremen­dous amount of pres­sure to this over­lap, re­sult­ing in two types of fric­tion that must be over­come for the gun to fire. Static fric­tion keeps the ham­mer from mov­ing against the sear pre­vent­ing the ham­mer from ro­tat­ing forward. Ki­netic fric­tion re­sists the move­ment of the sear against the ham­mer.

De­creas­ing the over­lap short­ens the pull dis­tance and de­creases fric­tion be­tween the sear and ham­mer. In­creas­ing the ham­mer/sear over­lap will in­crease fric­tion and the dis­tance the trig­ger has to travel to drop the sear. This travel dis­tance is also known as creep. In a per­fect world you want as lit­tle creep as pos­si­ble to have a crisp, clean break. The con­cern, how­ever, with hav­ing so lit­tle pur­chase be­tween the sear and ham­mer is that the static fric­tion might not be enough to keep the ham­mer from ro­tat­ing forward should the rifle be dropped or the trig­ger oth­er­wise moved. To pre­vent this we can ei­ther in­crease creep and/or in­crease the pull weight, a del­i­cate bal­ance be­tween safety and per­for­mance.

Fric­tion Fight­ers

Walk­ing the ra­zor’s edge be­tween per­for­mance and safety means mit­i­gat­ing fric­tion. That’s where the Cana­dian ma­gi­cians at Trig­gertech come in. It seems that the folks in the Great White have a pretty good grip on the physics. Specif­i­cally Trig­gertech’s de­sign uses a stain­less steel roller bear­ing be­tween the sear and ham­mer to nearly elim­i­nate the fric­tion be­tween these two sur­faces. There’s a very good rea­son they call it Fric­tion­less Re­lease Tech­nol­ogy, or FRT for short.

To un­der­stand how this makes a dif­fer­ence in re­duc­ing fric­tion, imag­ine push­ing a large con­crete block across the street. It takes a con­sid­er­able ef­fort to over­come the fric­tion be­tween the street and the block. But when you put wheels on the block, the ef­fort to get it across the street is sig­nif­i­cantly re­duced. It seems pretty ob­vi­ous.

With a roller bear­ing be­tween the sear and ham­mer, there’s a near fric­tion­less trig­ger ac­tion. There’s no need to play around with how the ham­mer and sear over­lap each other. With the re­la­tion­ship of the sear and ham­mer re­main­ing con­sis­tent and only the pull

weight to be con­cerned about, safety is no longer com­pro­mised for the sake of per­for­mance and creep can be con­sis­tently kept to a min­i­mum. Heavy pulls are smoother and light pulls are safer be­cause sear/ham­mer en­gage­ment has re­mained con­sis­tent.

Ad­di­tion­ally, be­cause there’s vir­tu­ally no fric­tional force to over­come, the trig­ger is not de­pen­dent on me­chan­i­cal ad­van­tage to move the sear. The re­sult is a marked re­duc­tion in creep. The com­par­i­son has been made the trig­ger feels more like a cus­tom 1911 trig­ger. Elim­i­nat­ing creep also cre­ates less wear and tear on the trig­ger group as a whole.

Trig­ger Re­set

An­other im­por­tant part of trig­ger group func­tion is how the trig­ger re­sets. Again, fric­tion and over­lap are the en­e­mies of a de­fined re­set. Af­ter all, it’s no good to make the rifle go bang if the fol­low up shot is slow and slug­gish, wait­ing be­cause the trig­ger is caught up get­ting to its orig­i­nal forward po­si­tion. The FRT also re­duces fric­tion on the way back, al­low­ing for a smooth and de­fined re­set.

A key fea­ture of many drop-in trig­ger groups is the abil­ity to ad­just the weight of the trig­ger pull. Usu­ally this is done by turn­ing a set screw tighter or looser to get the right pull. Some­times it can be a shot in the dark de­ter­min­ing ex­actly where your pull is set.

Trig­gertech takes the same prin­ci­pal found on scope tur­rets and ap­plies it to the set screw. When turn­ing the screw to ad­just the pull weight, you move through a se­ries of clicks. Each pos­i­tive click adjusts the pull by 2 ounces, with a high mark of 5 pounds and a low of 2.5 pounds (Model: Adapt­able AR Pri­mary trig­ger) that gives the shooter 80 points of ad­just­ment.

I can hear the ques­tions start­ing to pop the synapses in your gray mat­ter. “Sure adding a cou­ple of parts may add to the over­all per­for­mance, but that doesn’t mean much if it’s not go­ing to last.” Trig­gertech’s test data shows that af­ter 50,000 shots, there was no no­tice­able change in move­ment in the trig­ger pull or change in the pull weight. But that’s their data. What about real world?

Per­for­mance On Tar­get

I dropped two dif­fer­ent Trig­gertech trig­gers into my SMOS GFY16 (smosarms.com) and ran through a cou­ple thou­sand rounds. Though not nearly as many as the com­pany’s tests, I thought it would give me a good idea of the group’s dura­bil­ity and per­for­mance, es­pe­cially be­cause I didn’t clean the rifle dur­ing the process. In a nut­shell, the groups per­formed as ad­ver­tised. The per­for­mance was con­sis­tent with a smooth pull even when car­bon was al­most flak­ing off of the bolt car­rier group.

As much as I don’t want to, I get ex­cited about the new­est fea­tures and hyped up doo-dads to throw on my ri­fles. Gen­er­ally, how­ever, I’m un­der­whelmed and re­al­ize that I’ve once again bought into the marketing hype. With these trig­gers, how­ever, I got ex­actly what I was told I’d get and a lit­tle more. Don’t take my word for it. Af­ter all, trig­gers are ex­tremely per­sonal, but Trig­gertech is def­i­nitely worth the con­sid­er­a­tion. TW

“KNOW­ING WHEN YOU ARE ABOUT TO BREAK A SHOT IS CRIT­I­CAL FEED­BACK WHEN SHOOT­ING FOR PRE­CI­SION AND WHEN SHOT TIM­ING IS CRIT­I­CAL.”

Trig­ger styles are very per­sonal things. For me a flat blade ad­justable trig­ger fits my needs.

Just like the old “vis­i­ble man” toy, this dis­play model of the Trig­gertech sys­tem shows of all the in­ner work­ings.

A sim­ple turn of a hex wrench and you can ad­just to your de­sired pull weight. The CLKR fea­ture adjusts at 2 ounces per click.

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