COLT_AR15_A2

I have seen a lot of postings about unreliable AR-15s from people who intend on using them for "serious" purposes. Most often these problems can be repaired or were avoidable in the first place if you know what to look for when choosing an AR-15. My goal with this article is not to upset those who made "less than ideal choices", but to inform those who are considering relying on an AR-15 with their life. If your rifle is not one of the ones I list as being reliable enough, there will be a paragraph dealing with how to upgrade it to spec. The rifles I discuss may not be true ‘tack drivers’ but all are capable of 1 MOA groups with the proper ammo, or sub 2 moa groups with decent quality ball ammo. There are four things to consider if you want a ‘reliable’ AR - the rifle itself and what features it contains, your magazines, your maintenance/cleaning, and your ammo selection. We will trade-off some accuracy for reliability, and ‘cosmetic looks’ for functioning and durability.

Too often people judge rifles by ‘fit & finish’ or form over function. For a serious rifle you must ignore the superficial cosmetics and go to the working parts. First off what is needed for a "serious" AR-15? There are several features that should be considered, these features are all present in Military M16s, but not in all civilian AR-15s. In order of importance (IMHO) they are: M16 sized chamber, chrome lined chamber, mil-spec heat treated fire control parts, chrome lined bore, a chrome lined bolt carrier, and standard sized fire control pins. The ‘serious’ AR should have a forged lower receiver and a forged front sight for maximum strength.

One other feature a working rifle should have is a lightweight (not HBAR) barrel, a minimum of 14.5" of barrel length (flash hider/muzzle brake not included), and 1:9 or 1:7 twist. We will talk more on this in other paragraphs, and how to get one if you already have an HBAR.

4150 barrel steel is a "nice to have" feature, as opposed to the lower grade, less expensive 4140 steel. It’s not a critical feature, but the barrel will last longer.

Of all those features, only one manufacturer currently gives you all these features, two others come close. If you buy a rifle (or kit) from someone other than those listed you are taking some chances with reliable operation and long-term wear. The least ‘compliant’ of the Big Three manufactures surprisingly is Colt! Colt no longer chrome lines the bores of their rifle (gives a bit more accuracy), and their fire control pins are usually (90% of the time) non standard (limits parts availability). Lately they have also been a bit cheap on the trap door butt stock and buffer, but at least are now offering the rifle with two push pins to separate the receivers. Note that older rifles may have the chrome lined bores, and may not have the font take down pin. Colt usually has the best quality control (though they have been slipping a bit lately), but the worst customer service (good thing they usually make the rifles right the first time!). Colt is a good choice if you are looking for the most accuracy possible. The next manufacture to consider is Armalite, but only those rifles with the chrome-lined chambers & bores. Note I said Armalite, NOT Eagle Arms, while they come from the same factory the Armalites have the chrome lining in their barrels. Don’t let the clerk try to sell you the more accurate rifle with the stainless barrel - You want reliability over accuracy. The only point where the Armalites fall short is in the chamber. While Armalite has repeatedly promised, during the last 2 years, they were going to the M16 spec chamber in their chrome-lined barrels. Well recently they admitted it had not yet been done (but its coming soon…). Armalite is the only one of the ‘Big Three’ to not use the mil-spec 4150 steel in their barrels. The tougher steel is nice, but not critical in this rifle, as the chrome lining will help extend the wear. On the plus side they do have a lifetime warranty and better quality control than the last of the Big Three. The last of the Big Three is Bushmaster. Bushmaster is also the ONLY one to offer all of the desirable features, and is the closest to the rifles used by the US military. You want to select a model that has a chrome lined bore (this leaves out the DCM rifle and the new Varmint rifle). Bushmaster also offers several ‘lightweight’ barrel options for post ban rifles (16" M4 barrel {best}, the M4/AK barrel, and the M4 Dissapator [16" barrel with rifle sight radius]). They also offer all their HBARS in fluted form for a modest weight reduction. By the way in 1999 Bushmaster made more AR-15s for the commercial market than ALL the other manufacturers (in the US) combined. With such a large number of rifles produces sometimes little things get by. The biggest complaint is the barrel is improperly torqued, resulting in a rear sight that is all the way to one side when zeroing. I don’t worry about it, if you do then send it back. Bushmaster has great customer service and is quick about fixing any glitches or problems. Note even the Big Three occasionally turn out a lemon - it happens to the best of manufacturers. All of them will take the rifle back and get it fixed (though it may take a while with the Colt). Just be sure to maintain them properly and you should have minimal (near zero) problems.

OK so you already have an AR and want to upgrade it to make it more reliable. First lets talk about part suppliers. Many are indicating the parts they get are ‘FN’ Manufactured (they hold the current M16A2 contract for the US Army). BEWARE OF ANYONE SELLING "FN" PARTS/BARRELS/RECEIVERS - AVOID THEM LIKE THE PLAUGE. FN is prohibited from selling rifles or parts on the commercial market. FN can not legally produce AR-15s, so all their fire control parts are M16A2 (thus not legal in a typical AR-15). Any parts that are ‘truly’ FN produced were either stolen, or were factory rejects that were sold as scrap. Buying stolen item is never a good idea, and using what may be factory rejects isn’t smart either. Do you want to bet you life that ‘FN’ barrel you bought doesn’t have some sort of flaw in the steel? Another point to consider. Most AR parts are not marked as to the manufacturer, many shady dealers sell their parts as ‘FN’ knowing no right minded person will buy ‘factory seconds’ or ‘ cheap imported parts’. A word to the wise - stick with the big three for parts.

First thing to consider upgrading is the barrel (replacement cost about $200). While this might seem like a good sum of money, you got to think what is your life worth? Plus you could always sell the old barrel on the ‘net and recoup some of your costs. A new ‘in spec’ barrel gets you a chrome-lined M16 sized chamber, a chrome lined bore, a forged front sight, and often a lightweight profile. There are only two brands to consider Colt or Bushmaster. Many of the Colt aftermarket lightweight barrels are chrome lined (completely), and their military (A2 or M4) barrels are fully lined. The biggest difference between the two is the twist rate. Most Colts are 1:7, this will stabilize 55gr and 62gr rounds, and will stabilize the M856 tracer and the 80gr match loads. Unfortunately under rapid/heavy fire the barrel will ‘burn out’ quicker than the now common 1:9 barrels. Bushmaster is a big proponent of the 1:9 barrels as they’re optimal for 62gr loads (i.e. M855/Nato SS109) and will handle 40gr varmint loads up to 75gr match loads. It should have a longer barrel life given the same shooting conditions as the 1:7. Now when selecting a barrel you DO NOT want an HBAR. The AR is intended as a lightweight rifle, and the extra weight offers little. The difference between an HBAR 20" rifle and the same rifle with an A2 barrel profile is 1 pound - that is an empty HBAR rifle weighs the same as a fully loaded (30 rounds) A2 barreled rifle, quite a difference.

If you are unsure about the quality of your parts you can buy internal parts sets from Armalite, Colt and Bushmaster (cost around $60). This will ensure that your parts will not ‘wear out’ prematurely (you can keep the old ones as emergency field spares). Be sure your bolt carrier is chromed lined (in the area the bolt resides), if it is not lined or the hole is not round (i.e. oval) then replace it with a quality (in-spec) unit.

There are several parts out there that are sold as ‘upgrades’ and ‘better than spec’. Most of these parts are intended to separate you from your money with little to no improvements offered, and a possibility of reduced reliability. These parts include Chrome plated bolt carriers, Chrome plated bolts, TiN coated parts (bolt carrier, fire control), and Titanium firing pins.

Save your money and keep the rifle reliable - use standard parts from quality vendors.

Another area people want to upgrade is their extraction. This is especially an important thing to look at for carbines with their shortened gas system. There are three ways to do this. The first is the mil-spec way, by replacing your current extractors (with the blue insert in the extractor spring) for the newer extractors with the black insert. The black insert was originally developed for the M4 carbine, but works in all AR-15s and is the only replacement part the military is now buying. Cost is $4 from SAW LE Sales (http://www.SAWLESALES.com). The other two methods are designed to be used with the older blue insert. They are the Armforte Defender ($14) and the Olympic Arms EXring ($1.49). Basically they work the same, they go around the extractor spring and add more force to the extractor. Personally the easiest and best way is to get the mil-spec part, but having a few EXrings on hand as spares isn’t a bad idea.

Trigger upgrades are something most people want for a more accurate rifle. That is fine; just remember your ‘upgraded’ trigger should not have any screws to adjust. Screws have a tendency to come loose at the wrong time (Murphy principal). There are several ways you can upgrade your trigger and still keep the rifle ‘military’ reliable. The first is to just polish the trigger pin and smoothen out the pull. The other was is to get one of the replacement triggers that do not have screw adjustments. If you want a double stage type trigger consider either the Armalite or Rock River Arms trigger. If you just want a better single stage then look to the one offered by Accuracy Speaks.

Speaking of triggers you know that open area just behind the trigger guard and in front of the pistol grip? Yeah the one that can give you blisters if you carry your rifle all day (like at an urban rifle class). Well you can solve the blister problem either by stuffing a foam earplug in there, or spending a couple of bucks and buy a Gapper (available from many sources). The Gapper fills the void and prevents the blister. This doesn’t affect reliability or durability, but it does making holding the rifle for long periods much easier.

There are three other parts you should be aware of. Normally these parts are made of aluminum, but in some cases plastic is used. Depending on the part that could be a good thing. The first part is the Trigger Guard. Traditionally that part has been aluminum. Bushmaster currently uses plastic (they claim it is allowed by the mil-spec). Personally I prefer the plastic. The aluminum can be bent in such a way that it blocks the trigger (not a good thing!). If the plastic is bend beyond the breaking point it snaps; it may be broken - but it won’t block the trigger. The next part that is often replaced by plastic is the magazine release. Aluminum is preferred here, but it is not a big issue. The Delta Ring is the final part that is often replaced by plastic. This part is subject to being hit on rocks and should be aluminum for maximum durability. The chief problem is it is very difficult to replace (you will need to remove the front sight post). Best bet is to get it replaced when you have your HBAR re-profiled.

Magazines are a critical part in the reliability of any semi-automatic firearm; this is especially true with an AR. To insure reliable feeding DO NOT PURCHASE aftermarket magazines. These may be used for training purposes just fine, just don’t rely on them with your life. There are only 3 magazines I would consider for a reliable AR. USGI 30 round aluminum, USGI 20 round aluminum, or 30 round US produced Thermolds (not Orlites). Theoretically the steel FNC 20 round magazines (European military issue for the FN-FNC 5.56mm rifle) should also be fine, but I have not found any for sale in the US. USGI 20 round magazines include those used by the military (alloy follower) and the Colt commercial magazines (with plastic follower). The military ones are a bit more reliable due to their alloy follower. The 20’s in general are considered more reliable than the 30’s due to their straight walled design. The 20’s weak point is the feed lips, they are unsupported at the rear and will tend to wear out (spread) earlier than the USGI 30s. The USGI 30’s are the most common magazine. Thermold magazines, a hard black plastic magazine, were intended to replace the USGI aluminum ones. I find the 30 round versions made in the US to be very reliable, the 20 round version are not so reliable and should be considered 2^nd tier (along with the Orlites - softer black plastic) suitable more for training. I have reports from soldiers in the field that the Canadian produced Thermolds (have a maple leaf stamped on them) are less than durable. Their lips wear out quickly, and they cannot be stored loaded for long periods of time (the stress bulges the magazine at the feed lips resulting in double feeds). I have not noted these problems with the US produced magazines (marked Master Mold), but I don’t have nearly as much field time with them as my source.

When buying magazines there are some items you should inspect, and some you should ignore. Here is how to check for a magazine.

Like with all things if you feed it garbage, don’t expect high performance. Ammunition like Wolf (steel cased) usually feeds fine in ‘in-spec’ rifles. It is cheap blasting/training ammo, though it is very dirty and underpowered. However to insure full reliability and performance stick with mil-spec (or close to it) ammo. Even the clean/accurate commercial ammo (like American Eagle) should only be regulated to training as they lack the flash retardants and muzzle velocity of the military loadings. Military spec (M193) ammunition includes Winchester Q3131 (made in the USA), Winchester Q3131A (made in Israel by IMI), and IMI M193 and IMI M855 (62gr). Of all these I prefer the Winchester Q3131A it is of higher quality (IMHO) than Q3131 and it generally costs less than the IMI M193 (though it’s the same stuff). Stay away from the 1999 lots of Winchester Q3131 (USA produced). I’ve found there was poor quality control and different lots have had problems (including popping primers). Some of the lots were known, but others have just been discovered (2 years after production). As a rule its just best to avoid the 1999 lots for maximum dependability. Another good inexpensive load is the South African military ammo (in the brown ‘battle packs’). It seems identical to M193, and if nothing else its cheap, CLEAN, practice ammo that shoots to the same point of aim as M193. This stuff is 20 years old so I wouldn’t be using it for long-term storage, but it shoots well.

Many people think that the AR is only reliable when it is spotless. The rifle should be cleaned, but it does not have to be spotless. A typical cleaning should take no more than 15-20 minutes and 6 to 8 patches for the bore! Any more and you are probably over cleaning it (not necessarily bad, but it really doesn’t help). First off, follow the Operators Manual (-10) for cleaning AND lubrication (you can down load it for free from http://www.ar15.com). Many people want to clean and lubricate the rifle like it was a match rifle. That would be fine if it were such a beast, but we are talking about a reliable weapon, not a range toy. Be sure to use CLP (either Break Free CLP or Remington Nitro CLP - be sure the bottle says ‘CLP’). DO NOT use any other lubricants or solvents, these can react with the CLP and really gum things up. Areas to pay attention to include the chamber, locking lugs, end of the gas tube, bolt, extractor, cam pin, and bolt recess (in the bolt carrier). Be sure to lubricate the ejector on the bolt face (instructions are in the -10). These are the areas most critical for reliable operation of the rifle.

When cleaning the barrel you should only need 6 to 8 patches. If the patches come out a little gray that is OK. CLP is constantly pulling carbon out of the pores, even if you were to get a white patch, if you ran a patch down the bore the next day it would come out gray (from stuff the CLP pulled out of the fissures and pores). If you do need to clean out the copper (rarely needed - only when the groups start to open up, about 2000-3000 rounds) be sure to strip the barrel and upper receiver of the copper solvent by using Gun Scrubber or similar degreaser.

If CLP is not available then LSA would the second choice. When changing lubricants to or from CLP remember to strip off the old lube with Gun Scrubber or another degreaser to prevent gumming.

(1)	Extractor Pin
(2)	Extractor
(3)	Extractor Spring Assembly
(4)	Ejector Pin
(5)	Ejector
(6)	Ejector Helical Spring
(7)	Bolt Rings
(8)	Bolt

This guide is is created to help put together an AR-15 lower receiver from a stripped receiver and a lower receiver parts kit.

Tools

There are a few tools that make it easier to put together these kits, but none of them are necessary. Minimum requirements include a hammer and punch to drive in a couple of roll pins, a flat-blade screwdriver for A2 stock screw, and either a screwdriver or Allen key for the pistol grip screw. Specialized tools are available from Brownells, at 515-623-4000.

Roll Pin Punches - to drive roll pins (3/32", 1/8", 5/32"); these have a small raised projection in the face of the punch to automatically center the punch and prevent the roll pin from collapsing
Roll Pin Holders - used to hold and start roll pins... very convenient
Hammer - used to drive the roll pins
#10 Flat-Blade Screwdriver - used for A2 stock screw and some pistol grips
Block of wood - base to support receiver when driving roll pins
Pivot Pin Installation Tool - handy tool if you build a few lowers
Allen Key - used for some pistol grips
Telescoping Stock Wrench - to tighten telescoping stock lock ring

The Parts

The lower receiver parts kit consists of 30 parts not counting the stock assembly, the receiver, or the pistol grip. It is a good idea to lay all your parts out on a flat, light-colored surface so that you can verify all your parts are there, and find them easily when you need them.

Most parts kits come covered in oil to prevent rust; wipe all the excess oil off before assembly. Because of tight tolerances, some of these parts will be a tight fit. With the exception of the roll pins, no part should need to be hammered into place.

SPRINGS

Bolt Catch Spring - easily confused with the disconnector spring; disconnector spring is tapered though.
Buffer Retainer Spring - second largest spring in the kit.
Disconnector Spring - similar to bolt-catch spring, but identifiable because one end is wide than the other.
Hammer Spring - larger of the two similar springs.
Magazine Catch Spring - this is the largest spring in the kit.
Pivot Detent Spring - same as the takedown detent spring, so there are two in a kit.
Selector Spring - similar to the takedown and pivot detent springs, but there will only be one of these.
Takedown Detent Spring - same as the pivot detent spring, so there are two in a kit.
Trigger Spring - the smaller of the two similar springs.

PINS
Bolt Catch Buffer
Bolt Catch Roll Pin - smaller of the two roll pins.
Hammer Pin - same as trigger pin; can be inserted from either side.
Pivot Detent - same as takedown detent; both sides usually rounded.
Pivot Pin - larger of the two large pins.
Selector Detent - one end is flat, the other pointed.
Takedown Detent - same as pivot detent; both sides usually rounded.
Takedown Pin - smaller of the two large pins.
Trigger Guard Roll Pin - larger of the two roll pins.
Trigger Pin - same as hammer pin; can be inserted from either side.
Bolt Catch
Buffer Retainer
Disconnector
Hammer - will have a J-pin already installed.
Magazine Catch
Magazine Catch Button - some are plastic, some metal.
Pistol Grip Lock Washer
Pistol Grip Screw - some are Allen-head, some use a slotted pan-head screw
Selector
Trigger
Trigger Guard - some are metal, some plastic. Will already have a detent installed on its front end.

Assembly

The steps for assembly are presented in a sequence which has been effective. It is by no means the only correct method, as it does not make any difference on the end result if the magazine catch is installed before or after the bolt catch for instance. It is important to install the selector before the pistol grip, and a few other steps that must be performed before others. Unless you are experienced, follow the sequence presented and you will be successful.

Always work in a well-lit area, and it is helpful to work on a flat, hard surface. There are many small pins and springs, and they have a tendency to roll or fly away and disappear forever... In addition, look over the lower receiver before you begin the assembly. Many of the small holes can have debris in them from the forging process; a small drill bit, turned by hand, will clean these out nicely.

Magazine Catch Assembly
Trigger Guard Assembly
Bolt Catch Assembly
Pivot Pin Assembly
Trigger Assembly
Hammer
Selector
Pistol Grip Assembly
A2 Stock
Telescoping Stock

MAGAZINE CATCH ASSEMBLY

PARTS: magazine catch, magazine catch spring, magazine button
TOOLS: 5/32" roll pin punch

Install magazine catch into recess on left of receiver.
Install spring onto threaded portion of magazine catch from the right side of receiver.
Screw button onto threaded portion of magazine catch 3 or 4 turns.
Use a punch (larger than hole in magazine button) or wooden dowel to push in the magazine button so you can turn the magazine catch clockwise until the end of the catch is flush with the magazine button head. You can hold the receiver and press the punch against the table to do this, but put something between the punch and the magazine catch button to prevent marking it. Do this step first, as it will prevent the bolt catch from getting in the way as you turn the magazine catch into place.
CAUTION:
IT IS POSSIBLE TO SCRATCH THE RECEIVER ON THIS STEP!
Take special care when turning the magazine catch to avoid rubbing against the hump around the bolt catch.

FUNCTION CHECK
Check that depressing the magazine release button will push the magazine catch out of the magazine well in the lower receiver.
Spring will return magazine catch to engage in magazine well.

TRIGGER GUARD ASSEMBLY

PARTS: trigger guard assembly, roll pin
TOOLS: 1/8" roll pin punch, hammer

Attach front of trigger guard assembly to the receiver using the detent.
Lay receiver on a block of wood, and drive roll pin into receiver and rear of trigger guard using drive pin punch.
Make sure that the small block of wood is supporting the bottom flange and that the trigger guard is in position supporting the top flange otherwise you risk bending or breaking off one of the flanges.
Also watch as you put in the roll pin that it is going through the hole in the trigger guard correctly.
FUNCTION CHECK
Check that by depressing the detent on trigger guard you are able to pivot the trigger guard open.

BOLT CATCH ASSEMBLY

PARTS: bolt catch, bolt catch buffer, bolt catch spring, roll pin
TOOLS: 3/32" roll pin punch, 5/32" (or larger) punch

CAUTION:
IT IS VERY EASY TO SCRATCH THE RECEIVER ON THIS STEP!
Take special care to make sure pin in in place before driving it, and ensure that it is held securely in place when striking the punch. Fiberglass packing tape - 2 layers thick - taped over the receiver just between the receiver and the punch can help avoid scratching.

When installing the bolt catch, first drive the roll pin about halfway into the rear hump from the rear of the receiver using roll pin holder. It can be very difficult to get this pin started; you might want to try squeezing the roll pin on one end with pliers or the vise before starting. If you don't have a roll pin holder, then try holding it in place with a pair of needle nose pliers while you drive using a 5/32" punch.
Install spring in hole on left side of receiver.
Install bolt catch plunger on top of spring with round portion on top and small end into receiver. Make sure it moves freely in its hole.
Install bolt catch in receiver; it only fits on one way.
Use a 3/32" punch to hold the assembly by placing it through the front hump.
The pin can be driven the rest of the way from the rear as the punch will be pushed out and while holding the bolt catch in correct alignment. (function check as you do it to make sure it's going in correctly)
Avoid marring/scratching lower by covering receiver with tape, cloth, or other material while you do this.
FUNCTION CHECK
Verify that the bolt catch functions smoothly and is under tension from the spring.

PIVOT PIN ASSEMBLY

PARTS: pivot pin, pivot pin detent, pivot pin detent spring
TOOLS: pivot pin installation tool, 3/32" drive pin punch

This is perhaps the hardest part of the lower assembly, so if available, install the installation tool.
Insert spring and detent into receiver.
Compress detent in recess using 3/32" punch and rotate tool.
Push out tool with pivot pin and rotate until detent is in groove of pivot pin.
FUNCTION CHECK
Verify that the pivot pin detent prevents the pivot pin from coming off the receiver.
Note: If you do not have an installation tool, it can be difficult to get the pivot pin inserted without losing the detent and/or detent spring; if these parts do fly out, they can be very hard to find. The idea is to insert the spring and detent, and then compress them as you insert the pivot pin. A pair of needle-nose pliers can be helpful. It is difficult to remove the pivot pin once installed, so make sure you do it right the first time and make sure you've cleaned out the detent/spring hole with a drill bit before inserting the spring.

TRIGGER ASSEMBLY

PARTS: Trigger, Trigger Pin, Trigger Spring, Disconnector, Disconnector Spring
TOOLS: 5/32" drive pin punch

Shoulder trigger spring onto trigger with ends of spring forward and under.
Install disconnector spring with the wider portion of spring down towards trigger and push until it locks in there.
Position disconnector on top of trigger, where trigger pin will hold both in place.
Insert trigger assembly into receiver.
Insert trigger retaining pin through receiver, trigger, and disconnector. The trigger pin has 2 grooves in it; one in the middle of the pin and one off to one side. It does not matter which way it is inserted, though common practice is to insert from left to right, with the groove to the left.
Insert hammer pin from opposite side to help align things as you push the trigger pin in and the hammer pin out. You will have to push down on trigger assembly to align the holes and get the pin in all the way.
FUNCTION CHECK
Make sure that the trigger pivots smoothly when depressed.
Verify that the disconnector pivots when pushed.

HAMMER ASSEMBLY

PARTS: hammer (with J-pin installed), hammer spring, hammer retaining pin
TOOLS: 5/32" drive pin punch

Install spring onto hammer, ends of spring to rear and shoulder on back of hammer.
Install hammer in receiver with feet pointing rearward away from hammer
Use 5/32" punch to retain hammer in place as you insert hammer retaining pin.
Like the trigger pin, you may have to push down and align the holes perfectly in order to push the pin in all the way.
Ends of the hammer spring will rest on top of the trigger pin, with one end in the groove on the trigger pin.
Inserting the hammer pin may require some effort, as the J-pin in the hammer will catch the grooves in the pin.
FUNCTION CHECK
Verify that hammer locks to the rear when pushed back.
Verify that hammer pivots forward when trigger is pressed.
Without releasing the trigger, push the hammer back again and verify that it locks (caught by disconnector).
Releasing the trigger should not cause the hammer to pivot fully forward (caught by trigger).
Hammer will fall when trigger is pressed.

SELECTOR ASSEMBLY

PARTS: safety selector
TOOLS:

With hammer cocked back, insert from left side of receiver, selector pointing up in the 'fire' position.
FUNCTION CHECK
Make sure selector rotates freely.

PISTOL GRIP ASSEMBLY

PARTS: selector detent, selector detent spring, pistol grip, pistol grip screw, lock washer
TOOLS: Allen key or flat-blade screwdriver (depends on your screw type)

Install detent, pointed end towards the selector, and the spring into the receiver from the bottom.
Carefully compress the spring with the grip and make sure spring fits into hole in grip.
Check the function of the selector with the grip held in place; if too tight (unable to rotate) you may need to either cut the spring, or clean out the hole in the grip.
Once feel is acceptable, secure the grip in place with the screw and lock washer.
FUNCTION CHECK
Verify selector is able to move from safe to fire and clicks in place. It should not move past the 'safe' or 'fire' positions.
With selector on 'safe', verify cocked hammer is not released when trigger is pressed.
With selector on 'semi', verify hammer is released when trigger is pressed.
NOTE: Selector cannot be rotated to 'safe' unless hammer is cocked.

A2 STOCK

PARTS: takedown pin, takedown pin spring, takedown pin detent, stock, buffer extension, retainer, retainer spring, buffer, buffer spring
TOOLS: #10 (or larger) flat-blade screwdriver

Insert retainer spring and retainer into recess in lower.
Install buffer extension, (buffer tube); press detent when necessary; torque to 35-39 ft-lbs add spacer onto stock tube, and insert stock.
Install takedown pin with groove to the rear and install detent and spring from the rear of the receiver.
Carefully compress the spring with the stock and secure the stock in place with the self-locking screw.
Insert stock screw from rear into stock.
With hammer down, insert buffer spring and buffer into buffer tube until retainer snaps up to lock it in place.
Function check on takedown pin and buffer retainer.

TELESCOPING STOCK

PARTS: takedown pin, takedown pin spring, takedown pin detent, telescoping stock, buffer extension, backplate, locking ring, retainer, retainer spring, buffer spring, buffer

TOOLS: Telescoping Stock Wrench

Insert retainer spring and retainer into recess in lower.
Install buffer tube, backplate, and locking ring onto receiver and depress retainer when necessary to get it to rest under the extension tube. Turn tube until it is about 1/4 turn past the correct location.
Install takedown pin with groove to the rear and install detent and spring from the rear of the receiver.
Backplate will now hold spring in place when you turn the extension tube back 1/4 turn.
Tighten locking ring using telestock wrench for a snug fit.
With the hammer down, insert buffer spring and buffer into buffer tube until retainer snaps up to lock it in place.
Function check takedown pin, stock, and buffer retainer.