5.56 Tech

Setup is simpler and easier to physically do than it may seem while reading the Tech Sections below.

 

A complete printed version of the info from 5.56 Tech and 9mm Tech is mailed with each order.

 

If you have questions call our Tech Support number 480.305.3236.  One call is typically all it takes to get you squared away in a couple of minutes.  Note - We do not do email Tech Support. 

 

 

 

Setup Methods:

 

Overview on how each method below works

 

Scroll down for step by step details

 

 

Setup 1 or Setup 3 with Mil-Spec or Geissele Triggers you can swap the mech to another AR that has a Mil-Spec or Geissele Trigger.  Setup 2 with a Mil-Spec Trigger you can swap the mech to another AR that has a Mil-Spec Trigger in it.   Setup 2 with LaRue MBT you can swap the mech to another AR with a LaRue MBT in it.

 

 

Cock hammer manually before starting any Setup Method.

 

 

Setup Method 1 - Standard Method.  We recommend the original Standard Setup Method 1 which is printed on the inside of the packaging where the lower cam leg lands on the trigger bar.  This is also outlined in the 5.56 Tech area below.  This setup method gives you the most flexability. 

 

Setup Method 2 - Disco Override Method.  Another setup method for those who only want to use Mil-Spec triggers.  When using this method you can still use it in multiple compatable ARs with Mil-Spec triggers.  The basic process for setting up as Disco Override is almost the same as the process for Standard Setup 1.  There are a few slight differences.  See below for details on the Disco Override method.  Disco Override with a Mil-Spec trigger can also be used as a fix if too much was taken off the lower cam leg during Standard Setup 1.

 

Setup Method 3 - No Disco Method.  The third way to setup your ARIZONA REGULATOR.  This is for running a Mil-Spec trigger in a dedicated FRT only rig.  With Mil-Spec trigger it will only run with the mech in the receiver.  The basic process is the same as Setup 1, less disco and spring removed from Mil-Spec FCG.

 

 

Do not adjust or modify the upper cam during any setup process.  Modifying the upper cam can create overall function and timing issues.

 

 

LaRue MBT Triggers Note - The MBT 25 has a tall pillar at the rear of the trigger body.  This is where the lower cam leg will land.  You have to take (approx +/- 0.300) off of the lower cam leg length to run LaRue MBT triggers.  See setup 2 for an idea of how it interacts.  Instead of landing on the Disco the lower cam leg lands on the pillar of trigger bar.  LaRue details in Setup 2 Below.

 

Geissele Triggers  Note - Geissele triggers are a different animal.  If you are only going to use a Geissele trigger look at Setup 2 for an idea how it functions.  Except that the disco on a Geissele gets pushed all the way down into the trigger body by the lower cam leg.  The lower cam leg pushes down on the trigger bar itself like Setup 1 or Setup 3.  Geissele details in Setup 2 Below.

 

 

Conditions that allow full drop in mech function, no mech lower cam leg length adjustment needed.  Setup 1 Mil-Spec trigger in loose tolerances gun.  Setup 1, 2 or 3 Geissele trigger in loose tolerances gun.  Setup 3 Mil-Spec trigger in loose tolerances gun.

 

Industry stack tolerances are what required us to engineer the ARIZONA REGULATOR the way we did.  We had to ensure everyone could use the same mech in their ARs regardless if thier rigs stack tolerances are loose or tight.  Most of the time once you set up your ARIZONA REGULATOR in one of your ARs you can just swap the mech back and forth with your other ARs. 

 

The exception to that is trying to go from one very tight rig to a very loose rig, it may not reset the trigger in the very loose rig.  There are ways around that also.  Call the Tech line and we will get you thru it.

 

We recommend if you are going to run it in multiple guns get them all together on the bench and make it run in one of them then drop the mech into the others and check them for smooth function.  You may have to take a couple thou off for it to function smoothly in a different AR that is tighter than the one you initially setup on.

 

 

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5.56 Tech Short Version:

 

How it works

 

Mechanics / Function: 

 

Requires full auto BCG.  Requires 5.0+ oz buffer.  Originally developed using standard Mil-Spec triggers.  Also works with LaRue MBT and Geissele SSA SSA-* S3G SD3G etc style triggers.

 

You fire one shot by physically functioning the trigger.

 

The BCG moves to the rear and engages ths cams of the out of battery safety.

 

The cams move your trigger into the safe position where the hammer and trigger reengage ensuring your gun cannot fire out of battery while also regulating your firing cycle to one shot per single function of the trigger.

 

The BCG moves forward, once safely into battery the BCG disengages the cams allowing you to physically function the trigger again to fire the next single shot.

 

 

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Setup Method 1 Standard Instructions: 

 

Instructions are also printed on the inside of the packaging insert.

 

Cock hammer manually before starting any Setup Method.

 

 

Verify safe condition, chamber empty, mag removed.

 

Clearance rear of disconnector to 0.040 +/- 0.010 behind and above spring well.

 

Selector in fire position.  Pop rear take down pin.

 

Manually cock hammer.

 

With upper cam in vert position insert into upper receiver pocket.

 

Close receiver. Push rear take down pin back in.

 

Slowly pull charging handle to rear while tapping trigger.

 

Feel trigger travel shorten then lengthen as BCG moves rearward.

 

If BCG stops or trigger goes solid prior to full travel remove a couple thousandths of material at tip of lower cam leg to trigger bar contact area.

 

 

 

Function Check: 

 

Lock BCG to rear.

 

Hit bolt stop to release BCG.

 

BCG goes forward and disengages mech.

 

Allows you to pull trigger.

 

Hammer drops.

 

 

The mech is engineered to be tough and durable it will force and torque its way thru the operation even if it is not set up properly and slightly binds / drags when you fire your AR.

 

When properly set up you should not feel resistance from the mech in the gun when you slowly pull charging handle to rear without touching trigger.

 

 

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Setup Method 2 - Disco Override

 

As stated at the top this is another method of setting up your ARIZONA REGULATOR.

 

This is also the same method we tell folks to use to get them out of a bind if they take too much off the lower cam leg during Setup Method 1 Standard procedure.

 

Cock hammer manually before starting any Setup Method.

 

 

The differences between the Setup Method 1 Standard above and Setup Method 2 Disco Override are:

 

No clearancing of Mil-Spec Disco tail

 

Cannot use Geissele triggers once you setup using Disco Override with Mil-Spec Trigger

 

Takes a bit more length off lower cam leg than Setup Method 1 Standard does (approx +/- .060) .  Do not just measure and whack the tip off the lower cam leg with a grinder.  Slowly work your way with a fine cut file step by step to set the mech up.

 

When setting up this way you will still use the same process as the standard setup.  Except there are a few differences.  Read entire Setup Method 1 Standard above or on the inside of the package insert before starting to setup using Setup Method 2 Disco Override.

 

When using the "trigger tap" feel check while adjusting lower cam leg length it will feel different.  There will be a little more resistance on things.  Trigger will still tap but not as freely.  Ensure you have trigger tap all the way thru the BCGs motion.

 

You will also have slight resistance all the way thru the motion.  Unlike the no resistance spec in the Setup Method 1 Standard.  Do not remove material from upper cam to try and eliminate the slight resistance.  This slight resistance is caused by the disco spring pushing the disco tail up into the lower cam leg which creates a bit of tension on the system as there is no gap between the trigger and the lower cam leg as the mech moves thru its travel. 

 

That slight gap is what governs the zero resistance guideline in the standard setup directions final free movement check.  No slight gap with Setup Method 2 Disco Override thus you will feel a litte resistance.  Not enough that you have to force the BCG thru it.  If there is that much resistance/bind then the trigger is going solid and you need to take a couple more thou off and try again until the trigger does not go solid at any point of the BCGs motion.

 

As you are slowly pulling the BCG rearward to check for smooth function you will notice that the BCG moves rearward smoothly then hits a slight resistance point/wall where the BCG will continute to move but under slight resistance.  That is where the mech starts to go thru its motions.  Slowly pull charging handle while tapping trigger.  If BCG stops or trigger goes solid remove a few thou and try again.  The mech changes phases very rapidly when using Disco Bypass.  It is harder to feel the trigger travel shorten, cross the apex, then lengthen again.  Happens fast as it is under spring tension from the disco spring. 

 

 

Mil-Spec Setup 2 Specific Note :

 

Above is written with disco spring in FCG just like when normally shooting your gun.

The tension of the disco spring pushing up on the lower cam leg puts tenion on everything and may feel odd.  You may not be able to feel as easily as I do when using Disco Override.

 

For Mil-Spec Setup 2 when you have the disco spring in the FCG and first put the mech in the receiver then go to close and push rear take down pin back in the receiver will close like our A2 does.  You will have to push down on upper receiver to overcome the disco spring tension to close the receiver.

 

To make this a bit easer you can take the disco spring out during inital setup.  Once you have everything running smooth like in the setup video then put the disco spring back in and you are good to go.

 

Once the mech is in then begin the slow pull charging handle process like in A2 Setup 1 video to complete your Disco Override Setup 2.

 

 

LaRue Specific Setup 2 Note:

 

For the LaRue MBT you will have a gap and receiver will not close yet.  The gap to close receiver will be about +/- .200.  Slowly work your way removing material from tip of lower cam leg until receiver closes.  Then go to the Setup 1 process and finish getting your gun functioning smootly.

 

 

Geissele Specific Setup 2 Note:

 

With Geissele the tension talked about above is a bit more.  The base process is the same for Mil-Spec Setup 2 or Geissele Setup 2.  The receiver will usually completely close like our A2 does before taking any material off the tip of lower cam leg.

 

Ensure the lower cam leg is in the up postion when you start out and each time you close the receiver.

 

Geissele will feel very different when you are doing the slow pull process to get smooth operation.  It will pull slow and smooth then hit a stopping point that can feel deceiving.  You can take too much off and come up short on this one if you are not careful.  See below remove disco spring during initial setup to better feel what is going on when doing the slow pull for clearance and trigger tap process.

 

This is due to the angle of the Geissele disco tail that the lower cam leg pushes down and out of the way.  The Geissele and mech run properly and smooth once setup and you get them broken in with some rounds down range.

 

During initial setup this angle will make it feel like the BCG stopped like normal and more needs taken off.  Usually no more needs taken off to setup a Geissele than what little bit is taken off in the A2 video for a Mil-Spec Setup 1.  We swap the same mech back and forth between a Mil-Spec Setup 1 and Geissele Setup 2 all the time.

 

To make Geissele initial setup easier you can use the same process as Mil-Spec Setup 2 and remove the disco spring.  Once you are functioning smoothly on the bench put the disco spring back in.  The lower cam leg will still land on the Geissele disco tail then push down on trigger bar as described in the triggers video.

 

 

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Setup Method 3 - No Disco

 

This is litterally Mil-Spec Setup 1 with no disco.

 

Dedicated Forced Reset Trigger Function Only

 

Doubtfull anyone uses this method but it does work.

 

 

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General Setup notes:

 

 

Trigger “tap”

 

It is a lot simpler and easier than it may seem.  Key point is to get enough trigger face “tap” movement at the apex of the mechs travel so it does not bind or create drag on the BCG.  Normally we setup to just clear the bind / drag point but a little more will not hurt you as noted below in the interchangeability note.

 

The mech is engineered to be tough and durable it will force and torque its way thru the operation even if it is not set up properly and it slightly binds / drags when you fire your AR.

 

When properly set up you should not feel resistance from the mech in the gun when you slowly pull charging handle to rear without touching trigger.

 

Do not stress about keeping it as close to the bind point as we normally do.  Get it to not bind or feel drag on BCG when you very slowly pull charging handle all the way to the rear while you do not have your finger on trigger and you are good to go.

 

This is where tapping the trigger comes in, if the trigger taps and moves at the apex of the mechs travel then you are not binding.  Thus tap trigger constantly while slowly pulling charging handle to rear, you will feel the trigger travel shorten as the mech reaches the apex of its operation then trigger travel will lengthen as mech continues past the apex of its operation.

 

To get an idea of what too much “tap” would be. With mech out of receiver, pull charging handle to rear and release it to set hammer.  Then put gun on safe then pull trigger and feel how far the trigger moves until trigger tail hits bottom of the safety.  If you shoot for less than a quarter to half of that distance max you are good.

 

When we set one up in ours we stay tight, the face of the trigger “taps” about the thickness of a playing card.  We take off a couple thou at a time .002 / .003 which for us is a couple very light strokes with a 4.00 long .500 wide fine double cut file followed with a fine stone to smooth out the filed surface, try it in gun again, if it binds or drags take another .002 / .003 off, try it in gun again.  In slow increments till we get smooth full travel feeling the trigger tap with zero bind.  Once we feel zero bind while tapping we slowly pull charging handle to rear while not touching trigger to ensure we feel zero drag on BCG for its full rearward travel.

 

Interchangeability: 

 

We had to shorten the lower cam leg a little extra for our 9mm config than we normally have do when setting one up in our A2 5.56 config.  The same mech still worked in the 5.56 setup afterwards when we changed back over to the 20” A2 config.  There was a good bit more trigger “tap” movement at the apex of the mechs travel than we normally setup up to in the A2.  Which subsequently shortened and lightened the trigger pull a bit when doing rapid fire.  Your results for interchangeability may vary from ours. 

 

 

 

BCG / Buffer: 

 

Standard full auto BCG is required to disengage the ARIZONA REGULATOR.  The smooth edged well made BCG's work best.  They function smoother overall.  But all standard FA BCG's we have tried functioned.  If your BCG is sharp and or rough at the release area smooth it out and polish if need be.  Sharp and or rough BCG's can create wear on mech top cam above and beyond normal break in and parts seating together from use.  No different than anything sharp or rough would do to another surface.  We have never had wear issues with the original BCG in our 20" A2 or with the 9mm BCG in that setup, both of which are smooth edged well made parts. 

 

Buffer weight does factor in during rapid fire.  We use a 5+ oz buffer with 5.56/.223.  We have found that in 20” A1 / A2 guns with a regular rifle buffer there are zero issues.  Everything runs perfect.  Once we went to another AR in true carbine config with carbine buffer tube, shortened up the barrel length, and or threw on a suppressor we had to go to an H3 buffer that weighed in at 5+ oz to eliminate bolt bounce.  It has nothing to do with slowing the bolt down and everything to do with mitigating bolt bounce. 

 

How do we know this.  Simple.  With a lighter H2 carbine buffer in the suppressed 12.5 SBR Carbine we ran into a last round light strike situation.  Did not matter if we ran 5rds 10rds 20rds 30rds.  The mag would run perfectly then last round would light strike.  This was due to there being no drag on the bottom of the BCG from the empty mag after it chambered the last round.  That slight bit of drag from a round in the mag pressing up against the bottom of the BCG was enough upward force and drag to counteract the last bit of bolt bounce while using a lighter H2 carbine buffer.  Ran perfect thru the mag then light strike last round every time with the lighter H2 carbine buffer.  Swapped to an H3 carbine buffer that weighed in at 5+ oz and never had any problems after that regardless of barrel length or adding a supressor on that AR Carbine. 

 

Thus for the reasons above is why we require a 5+ oz buffer.  Bottom line is if you are getting light strikes it is due to bolt bounce.  Increase the buffer weight till the bolt bounce goes away. 

 

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Questions and Answers: 

 

 

Q:  How do I use the full range of function of the ARIZONA REGULATOR. 

 

A:  It is an easily developed skill.  It is all in how you function the trigger for each shot.  For slow fire quickly function trigger.  For rapid fire slowly function trigger.

 

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Q:  When setting lower cam leg length the charging handle / BCG stops and trigger goes solid. 

 

A:  This is typical.  Remove a couple thou from lower cam leg length or contact surface of trigger bar. Either method works.  Removing from lower cam leg is easier.  Removing from trigger bar allows you to use one mech in multiple guns regardless if one is a loose setup and another is a tight setup. 

 

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Q:  When setting bottom cam leg length the charging handle / BCG stops but trigger still taps and moves. 

 

A:  This usually means the gun needs a little more Mil-Spec disconnector tail reduction for the lower cam leg to clear and contact the rear of the trigger bar.  Put some dykem or black sharpie on disco then slowly pull charging handle to rear till it stops a few times.  This will make a rub mark that lets you see where you need to remove a little more material from the disconnector tail to make lower cam leg clear Mil-Spec disconnector tail.  

 

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Q:  When setting lower cam leg length BCG doesn't stop and trigger taps the whole travel of charging handle.

 

A:  Gun is a looser setup than others.  You do not need to adjust lower cam leg length.

 

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Q:  After shooting a while my upper cam has some wear on the tip of where it contacts the BCG to disengage the upper cam.  More than normal seating of parts from use. 

 

A:  BCG is probably sharp and or rough at the disengagement area.  See BCG section above.  Swap to a smooth non sharp BCG or smooth your BCG with a fine stone or cratex.  Or if BCG is smooth and well made what you are experincing is a "torquing thru" situation.  The mech is engineered to be tough and durable it will force and torque its way thru the operation even if it is not set up properly and it slightly binds / drags when you fire your AR.  You do not have the proper amount of "trigger tap" and the mech is still binding and drags on BCG when slowly pulling charging handle to rear while not touching trigger.  Set lower cam leg length per instructions above. 

 

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Q:  When doing rapid fire I get one shot then a light primer strike on next shot. 

 

A:  Caused by bolt bounce.  Typical H1 buffer issue.  See buffer section above.  Is gun running the required 5.0+ buffer weight.  If so your gun may need a heavier buffer to get rid of bolt bounce.

 

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Q:  When doing rapid fire I get a light primer strike on last round in mag only.

A:  Caused by bolt bounce.  Typical H2 buffer issue.  See buffer section above.  Is gun running the required 5.0+ buffer weight.  If so your gun may need a heavier buffer to get rid of bolt bounce. 

 

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Q:  Too much material got removed during the Setup Method 1 Mil-Spec Standard "clearance disco" now it won't reset.

A:  See Setup Method 2 Mil-Spec Disco Override.  That will get you functioning.  Ensure you use a new Mil-Spec Disco. 

 

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Q:  Too much material got removed during the Setup Method 2 Mil-Spec Disco Override now it won't reset.

A:  See Setup Method 2 LaRue specific.  A LaRue MBT will get you functioning. 

 

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Q:  Too much material got removed during the Geissele Setup now it won't reset.

A:  Go to Setup 2 Mil-Spec Disco Override.  Or go to a LaRue MBT trigger see Setup Method 2 LaRue specific.  Both of those will get you functioning. 

 

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Q:  Mech won't fit into pocket in my upper. 

 

A:  Upper is not to standard Mil-Spec Print.  Swap uppers or see directions inside package for info on how to adjust mech to work with out of spec uppers. 

 

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Q:  Mech won't fit into my lower. 

 

A:  Lower is not to standard AR Mil-Spec print.  Or lower has the Colt block machined into it just forward of the rear take down pin/lug acceptance location.  Swap lowers if it has the block in it or see directions inside package for info on how to adjust mech to work with out of spec lowers.

 

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