FA91 RECEIVERINSTRUCTlONS FOR ASSEMBLY AND MAINTENANCE

INTRODUCTION

TOOLS AND PARTS REQUIRED

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TABLE OF CONTENTS

CONTENTS

LEGAL DISCLAIMER

B.A.T.F LETTER

G3/HK91 DIAGRAM

G3/HK91 PARTS LIST

G3 PARTS KIT PREPARATION

FA91 RECEIVER INSTRUCTIONS

FUNCTION TESTINGITROUBLE SHOOTING

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FEDERAL ARMS CORPORATIONOF AMERICA

7928 UNIVERSITY AVENUE N.E.FRIDLEY, MN 5543

Thank you for purchasing a firearm or accessory produd from FEDERAL ARMS CORPORATION OFAMERICA, INC. Please report any serial number discrepancy or shipping error as soon as possible.Notify carrier of any damage that may have occurred during shipping.

DEALERS-PLEASE INSTRUCT YOUR CUSTOMERS AS FOLLOWS

* ALL firearms are dangerous when handled improperly.

* CLEAN AND VISUALLY INSPECT all firearms before firing.* INSPECT the safety mechanism carefully to assure that it will

function properly.* FEDERAL ARMS CORPORATION HAS NO TESTING FACILITY

AND ASSUMES NO LIABILITY FOR THE SAFE FUNCTIONING OFANY FIREARM OR THE SUITABILITY OF ANY ACCESSORY.

* Read the directions through completely before attempting theinstallation of any accessory or part. If you do not understand anyprocedure or process, or if you are not qualified, do not attemptinstallation without the assistance of a qualified gunsmith.

* Due to the age, condition and diverse sources of surplus militaryfirearms and parts, dimensional incompatibility may indicate that theinstallation of an accessory or part is not compatible or appropriate.The person that installs the accessory or part assumes aliliabiitiy.

* Always use common sense when handling firearms. Treat everyfirearm as if were loaded. Always point the muzzle in a safe direction,and keep your finger off the trigger untill you have identified a targetand have determined that it is safe to shoot

The FEDERAL ARMS CORPORATION cataolg of items offered for sale includesfirearms (which are sold to FFL holders only), and accessories which require nospecial state or federal license to possess. Installation of an accessory may becovered by the National Firearm Act (NFA), section 922r of the Gun ControlAct(GCA), or other applicable statues.

It is the policy of FEDERAL ARMS CORPORATION OF AMERICA that anyinformation you may receive directly or indirectly from anyone associated withFEDERAL ARMS CORPORATION OF AMERICA is only given with the explicitunderstanding that both parties have the underlying intent to comply with allapplicable laws. Firearms and firearm accessories offered for sale are onlyoffered in a manner or condition consistent with federal and state laws, andintended for the following purposes:

"Repair of a legally possessed firearm."Making of an ATF Form 2, or an approved ATF Form 1 firearm."Construction of a non-functional replica non-gun."Making of a weapon by, or for the benifit of, a government entity."Completion of a NFA weapon using a registered receiver."Possession of a collectible curio, ornament or relic."Construction of a non-controlled art object."Possession of non-<:ontrolled parts for future use in legally making a firearm in

anticipation of change of laws by legislation or court ruling"Making of a weapon by a licensed manufacturer.

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B.A. T.F. LETTERDATED JULY 9,1998

This is in response to your letter of June 29, 1998, to the Bureau of Alcohol, Tobacco and Firearms(ATF), in which you request certain information regarding a purposed U.S. made parts kit for imported

semiautomatic SLG 95, SR-9 and other Heckler & Koch (HI<) type sporter rifles.

Trtle 18, United States Code (U.S.C.), 922 (r) prohibits assembly of certain semiautomatic rifles andshotguns from imported parts. The implementing regulations in Title 27, Code of Federal Regulations(CFR) part 178, 178.39, provide that no person shall assemble a semiautomatic rille or any shotgun

using more than 10 imported parts listed in paragraph (c) of this section, if the assembled firearm is pro-

hibited from importation under seelion 925(d) (3) as not being particularly suitable for or readily adapt-

able to sporting purpose. The 20 parts listed in paragraph (c) are listed below. Parts marked with "areused in the above-mentiones HK type rifles.

(1) Frames. receivers, receiver castings, forgings, or stampings". (2)Barrels"

(3)Barrel extensions. (4)Mounting blocks (trunnions)'

(5)Muzzle attachments. (6)Botts"

(7)Bott carriers". (8)Operating rods"

(9)Gas pistons(10)Trigger housing"

, (11)Triggers"(12)Hammers"(13)Sears"(14)Disconneclors(t5)Bultstocks"(16)Pislol grips"(17)Forearms. hand guards"(18)Magazine bodies"(19)Followers"(20)Floorplates"

On April 6, 1998, HK style rilles having an ability to accept a large capacity magazine were prohibitedfrom importation under the provisions of section 925(d)(3).Any such fireamns that were lawfully imported or lawfully assembled prior to April 6, 1998, may stili belawfully possessed. However, it is now unlawfull to assemble such firearms using more than 10 impart-ed parts as provided in section 178.39.

Based on the information that you provided, it appears that installation of a U.S. made (Handguard), pis-tol grip, trigger, sear, and (hammer),as you described in your letter, would result in assembly of a rillewith only 10 of the listed parts and would not constitute a violation of section 922(r). However, Installa-tion of any additional imported parts would be unlawful.

In addition to the above, we would caution you that a semiautomatic rille having an ability to accept adetachable magazine and at least 2 of the following features would be a .semiautomatic assaultweapon. as that term is defined in 18 U.S.C. 921(a)(30)(B):(i)a folding or telescoping stock;(ii)a pistol grip that protrudes conspicuously beneath the aelion of the weapon:(iii)a bayonet mount;(lV)a flash suppressor or a threaded barrel designed to accommodate a flash suppressor; and(v)a grenade launcher

II is unlawful to manufacture, transfer, or possess a semiautomatic assaull weapon except as providedIn 18 U.S.C. 922(r). A semiautomatic assault weapon that was lawfuDy possessed on the date of enact-ment of this subsection (September 13, 1994) may stiD be lawfully possessed and transferred. Anunmodified SLG 95, SR-9 or other similar HK type sporter rifle has only one of the qualifying features(the pistol grip); therefore, they are not.semiaulomatic assautt weapons. as defined and they do not

meet the exemption even if they were originally manufactured prior to September 13, 1994.

end of letter

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G3 parts preparationG3 parts k~s typically come with the barrel and cocking handle tube still attached to a portion of the oldsheel metal receiver. We will describe this part as the "ok! receiver assembly". Place the old receiverassembly into a vise with the cocking handle tube up. You will now need to scribe two marks on the

cocking handle tube and fronl sight assembly. Scribe

a mark, parallel to the barrel, across the sight assem-bly onto the cocking handle tube. Next, scribe a mark

around the tube, at the point ~ enters the rear of thesight assembly. The marks will be used later to posi-

tion the tube during re-assembly of the tube into thenew receiver. The next step will be to cut the cockinghandle tube from the ok! receiver.Use a hack s:iNi tomake the cuts. You will need to make three cuts. Thefirst cut witl be made behind the wek! area, on thereceiver side of the weld.This cut will be at a 90degree angle (perpendicular) 10 the barrel. Locate the

cut behind the weld area .250" ,not to exceed.300"(see photo detail of the enlarged picture of thecocking handle tube after ~ has been removed). The

second and third cuts will be along the bottom of thecocking handle tube area where it meets w~h the

trunion, altematively this couk! be described as the area where the small radius meets the larger radius.Cut both sides along the length of the ok! receiver,parallel to the barrel, this will allow the cocking han-

dle tube to detach from the trunionarea. The extra length of the cock-ing handle tube behind the wek!

area witl insert inlo the new receiv-er and "float in position". Theattachment of the cocking handletube will be accomplished by usingthe black aluminum plug providedwith your receiver kit. This plug willbe inserted into the face of thecocking handle tube and sightassembly and provide a secure

melhod of attachment. This wUI bedone at a later time.WELD AREA

~ AI this lime deburr the exterior ofthe cocking handle tube as weillas deburr the interior of the lube.Using a wire brush clllan and,scrape the interior ~f the fronl of

the cocking handle tube, makingsure thallhe interior is free of dirtand is thoroughly degreased, thiswill anow for the aluminum plug tobond to Ihe cocking handle tube.

See photo.I' .,' ',:; :." . Make sure

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~tjjJ §~knotch area. If this does not r~, continue to dress the outside diameter until it fils freely into the reciever,the proper diameter should be .900-.

~,= .250"

The next step is to remove the remaining portion of the old sheet metal receiver stUI attached to thetrunion. Use a large slotted screw driver to peel away the ok! receiver. After removing the old receiver,use a grinder or hand file to grind the face of the four exposed spot wek!s untill they are nush andsmooth with the rest of the trunion.

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G3 trunion and cocking handle tube preparationAt this stage you have removed the old receiver from the barrel trunion and havecarefully cut away the cocking handle tube to the dimensions required. Take timeat this point to examine the cocking handle tube to make sure that the tube isstraight and does not have any dents or bends and that the cocking handle sup-port moves freely through out the cocking handle tube. Install the cocking handlesupport into the cocking handle tube and assemble the cocking lever with thecocking lever spring using the cocking handle axle pin. Once assembled, test thecocking handle movement making sure it does not bind as it travels back andforth in the tube.

The G3 and HK91 style rifles have their barrel installed within a larger block ofsteel called the trunion. The trunion is also responsible for the lock up of the boltinto battery. and determines the head space. The trunion is attached to the bar-rel with a pin, called a barrel pin. Installation and assembly of the new receiverwill not require the removal of the barrel pin. The barrel pin has been inserted

through the bottom half of the trunion. To better aid in the insertion of the barrelpin and to allow for ease of manufacturing, the trunion has had two flat spot

machined into it The new FA91 receiver will utilize the flat spots alreadymachined into the trunion. You will drill two holes and insert two pins into thetrunion to properly secure it to the new receiver. The holes you drill will be 90

degrees relative to the barrel pin. The pins that you will install will be referred toas the trunion pins. Because of inconsistencies during the assembly process ofthe barrel and trunion, the manufacturer has often left the barrel pin at various

lengths that extend beyond the trunion. This could be a problem as you attemptto drill your trunion pin holes. If the trunion pins make contact with the extend-

ed portion of the barrel pin you would be unable to drill into the barrel pinbecause it is very, very hard. To prevent any problem you must grind the face of

the barrel pin down to a level flush with the trunion. We recommend a 1/8" diam-eter carbide cutter attachment and the use of a dremel tool. See photo.

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Once thebarrel pinhas beenground flushon bothsides of thetrunion.After this

"''''u'''''''''" step is fin-ished then use a hand file to flatten and smooth over the spot weld areas, pro-viding for a smooth concentric outer radius around the trunion. The trunionshould fit tightly into the new receiver but should not present too much resis-tance.With 100 grit sand paper roughen up the exterior surface of the trunion, this willallow better adhesion for the lock tite compound. You must dean and prepare thesurface of the trunion. Use a degreasing compound like acetate or alcohol and

clean the exterior sur-

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not intended to provide astructural benefit. Nowapply lock Ute compoundevenly around the exteri-or of the trunion. Une upthe cocking handle tubeassembly and slip it intothe face of the newreceiver. Visually refer-

G3 part preparation continued,~<:"

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ence the front site post, it must belevel and straight. Slide the barrelassembly, with the cocking handletube attached, into the face of the newreceiver. A dead blow hammer can beused on the muzzle end of the barrel,to seat the trunion all the way againstits final resting position, which is flush :::.against the internal rails. .';:

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To determine that the barrel trunion is "timed" correctly, and the front site isproperly aligned, shine light into the ejection port. To illuminate the barrel trunionand the rails of the receiver, Observe that the trunion is concentric and level withthe rails in the receiver. Also, check to see that the trunion has moved all theway back to its rear-most position flush to the machined surface of the face of

the rails in the receiver. Allow 24 hours for the lock tite to cure.

The next step will be to drill and pin the barrel trunion to the new receiver. First,place the new receiver upside down resting on the flat portion of the scope rail ina heavy duty machine vise. Do not apply an excessive amount of clampingforce, just enough to hold the receiver in place for drilling. The holes should belocated by using the predrilled starter holes. The dimension from hole to holeshould be within 1.250"-1.255".

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Using a sharp 5132" drill (provided) drill the firsthole through the new receiver. Use cutting oil and reverse out the drill onen to eliminatethe extra chips, drill .100" at a time then reverse out drill to reduce build up. Hole depth isaproximately 1 112", drill all the way through the receiver. \M1i1e drilling you may hit a hardspot, slow down your speed and use more coolant and a heavy feed pressure. The hardspots occur due to the spot welding of the old receiver during assembly. Clean out the newhole of chips. Now drive the pin into the first hole far enough to prevent the trunion fromrotating while you drill the other hole. Make sure that the groove portion of the pin is at theback(the side that you are hammering on) and that you do not drive the groove portion orthe pin In first. Once the second hole Is drilled, hammer in the second pin. Use a punch todrive the pins until they are nush with the receiver body.

p~,Now that the barrel trunion has been installed you can affix the cocking handle tube. Firstream out the existing hole on the side or the sight assembly, this hole was used for thespring latch retainer that held the old cocking handle tube cap, this cap will not be used.Instead you will insert the aluminum plug provided. Ream with a #19 drill or other reamerto open the hole large enough to allow the installation of the screw provided (the aluminumplug is tapped for the screw provided, do not use the self tapping screw,you will use this

screw elsewhere). Now apply locktite to the aluminum plug and insert the plug into the faceof the cocking handle tube, making sure to align the tapped hole with the existing hole Inthe side ofthe sight assembly. A dead blow hammer can be used to insert the plug all theway into the tube. Now check to varify that the cocking handle groove is at a 90 degreeangle to the sight post, and that your scribed marks line up on the h'ont or the cocking han-dle tube. Once the plug is inserted ,insert the screw and lighten.

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Now use a 1/8" drill bt to drill a hole inthe top of the cocking handle tube toinsert a screw to hold the cocking handletube to the plug.

Place the hole just far enough away from the iron site to allow enough clearancefor the head of the screw. Use a punch as shown in the above photo to locateyour position to drill.

To properly assem-ble the magazinerelease you musttake the magazinerelease spring andstretch it so that itretains a length of 1"in its resting posi-tion. Insert the mag-azine release springinto the magazinerelease hole in thereceiver, then insertthe magazinerelease and attachthe magazinerelease button withthe spring pinincluded in yourparts kit. We do notuse the G3 paddleparts(the paddlestyle mag. releasesystem that pro-trudes beneath thereceiver) whenassembling thisreceiver.Nowassemble the rest of the firearm.

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MAINTENANCE INSTRUCTIONSAND FUNCTION TESTING

The rlne should be unlO<llded and the safety engaged. Clean the barrel. cocking lever tube and mag-azine release lever and check the assembfies and subassemblies for proper seal.

Clean and oil receiver, barrel extension. and barrel. Also, oil the rear exterior 01 the receiver(lhe areawhere the butlstock assembly slides over the receiver) Ihis will help prevent damage to the paintedexterior surface of the reciever when you slide It on and olf.

Check function of cartridge feed and ejection, trigger mechanism and &arety by puDing back cocking

lever. The cocking lever must engage 6/TIOOIhly In the recess in the cocking lever housing. Rearwardmotion or the bolt must be friction-free. \MIen releasing the cocking lever, a practice cartridge must beproperty chambered. \MIen pulling back the ooclOOg lever, a practica cartridge musl be properly ejected.

W~h the sarety lever In poslion .E"(lire) ~ musl be posd>1e to squeeze the trigger and to overcome the

lel-olf pressure wilhout any restrictions. The safety lever must securely engage the position .s.(sare).

An impOltant reature to teslls head space. This can be accomplished by fll'sl removing the magazineand making sure thai the bolls completely seated In battery. Use a feeler gauge and Insert ~ Into thegap between Ihe bolt head and bolt head carrier. This area Is visible by tipping the rifle over to expose

the magazine weD area. Look into the magazine well and you wiDsee the bolt and bel carrier. The prop-

er gap should be between 0.1 and 0.5 nvn. II may not be possible to Introduce the reeler gauge 0.501111.If the gap will not allow any of the feeler gauges to be Inserted the rifle Is out of heads pac. andIs worn out. Firing the rifle under this condition Is dangerous, and may rasu" In damge to therlne. Firing the rifle out-or-tJeadspace will void the warranty or the receiver.

. SIGHTING-INOF THERIFLEPlace Ihe rear slghlln posilion "2.. Ulling a sighlln distance of 100 metelS adjusllhe poinl of Impactand zero in as foDOI/\/II.

Elevation adjustment:In68rt elevation adjulilmenttool inlo the rear slghl cylinder so lhatthe wedges of Ihe tool engage thetwo 510111In the cylinder which contain the catch bob. Press a PhDUp$-head screwdriver downward Intothe adjuslmenltool and hold rlml. Tum the rear lIight cylinder manuaUy In the desired direction. Tumingclockwise towel'll the point or impact 3.3 an(1.29 in.) per click al100 metefll(109 yds.),tuming counter-clockwise raises ~ correspondingly. Aller making the correctionll withdraw the PhDIip$-head screwdriverand remove elevation adjustment tool. The catch wil rlHlngage In the 1110111.Aller performing the eleva-tion adjuslment 1181the desired aperture again.

Windage adjustment:Ir the point or impact 16al the len: Loosen clamping screw on the top 01 the sight ba68. Tum adjuslJngscrew on the rlghtliide counter-clockwise In accordance with the required correction. Then retightenclamping screw.

If the polnl of impact is at the right: loosen clamping screw. Turn thead adjusting screw clockwise untlthe required correction has been performed. Then retighten the clamping lICfew.

Note: Each revolution or the adjusting screw moves the mean point of inpact 13.2 em (5.19 In.) to the

lell or right at 8 range of 100 melelS (109 yds.)..

TIPS"IF lHE SHEET METAl PORTION OF lHE BUTTSTOCK ASSEMBLY IS DIFFICUlT TO SUDE ON

. AND OFF, TRY LUBRICATING THE EXTERIOR OF THE RECEIVER IN THIS AREA. THIS IMLL.AllOW FOR lESS WEAR ON THE ANISH AND AllOW FOR EASE OF ASSEMBLY..IF lHE BUTTSTOCK STILL IS DIFFICULT TO SUDE ON, EXAMINE lHE SHEET METAl PORTION

FOR BENDS OR DISTORTION, WE HAVE NOTICE THAT MANY OF lHE G3 PARTS KITS HAVE

BUTTSTOCK ASSEMBLIES THAT HAVE BEEN BENT OR CRUSHED DURING SHIPPING AND

STORAGE. YOU MAY HAVE TO BEND OUT lHE SIDES OR TOP OF THE SHEET METAL STAMP-

ING TO FIT PROPERLY ONTO THE RECEIVER..ClEAN AND DEGREASE THE RIFLE AFTER EACH SESSION OF SHOOTING, AND OIL All

PARTS BEFORE STORAGE.

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