HK - G3 - Cetme Q & A


I created this page to answer some questions we are frequently asked.  Hopefully this info will be helpful in identifying any problems or concearns you have with your G3/HK/Cetme style rifle.  Please note I am not a gunsmith nor do I pretend to be one.  If the problem you have is not listed here you should consult a gun smith or ask online at www.militaryfirearm.com/ or www.HKpro.com .

Q: Does a Full Auto Lower or Full Auto Fire Control Group make my semi auto HK91/G3/PTR/Cetme full auto?
A: NO.  A full auto lower or full auto fire control group will not fit on your semi auto receiver.  Your semi auto receiver has a block welded on to ensure a full auto fire control group will not attach.  Modifying or removing that block to install a full auto lower is illegal unless you are a licensed machine gun manufacturer.  Please, please do not ask me how to make your semi auto into a illegal full auto...come on guys, common sense, don't ask me about this.

Q: Can I modify a full auto fire control group to semi auto?
A: YES!  Most HK gun smiths can convert full auto fire control groups to semi auto for a flat fee.  This modification can also be done by many home gunsmiths...to ensure the conversion is done to ATF specs I would recomend using a good gun smith.  Gun smiths who do this work can be found on our links page or you can find them online.

Q: What does a 'Clip & Pinned' lower do?
A: A clipped & pinned lower is a modified full auto lower.  Once modified and installed on a rifle this lower makes a HK style weapon appear to be full auto.  In reality the gun is still a legal semi auto using your existing semi auto fire control group.  This gives you the look or a real HK full auto while maintaining a legal semi auto.  Also clipped & pinned lowers are perfect for those using registered sears or trigger packs.

Q: How to remove Rollers on G3/HK91 or Cetme?
A:  1, Strip rifle and remove bolt assemble.
         2, Remove Bolt head from Carrier
         3, On the top of the bolt head you will see a small hole with a roll pin.  Using a small punch tap out the roll pin.  Retainer plate and rollers will now slide out.
         4, Shake bolt head until the roll pin falls out.
         5, Now put it back together, check your bolt gap and go shooting.

Q: How to check your Bolt Gap?
A: For a HK91, G3 or Cetme to run reliably and safely it should have a bolt gap that measures between .3 and .5 millimeters (about .012 - .020 Inch).  If your HK/G3 or Cetme has less bolt gap or no bolt gap than you need to change your rollers and use HK + Size rollers which are available for sale on our G3 Parts page.  Do not think that just because your rifle is working that your bolt gap is OK.  I myself didn't notice the bolt gap had totally disappeared on my favorite FMP G3.  I was shocked to see I had no bolt gap, a set of HK +2 Rollers got me back up to spec and now I can once again safely shoot my favorite G3.  The lack of bolt gap can not only be dangerous but it also increases the amount of wear that your rifle endures while firing.
    1, Remove Magazine.
    2, Pull back cocking handle and let the bolt slam shut, make sure it's shut all the way.
    3, Turn rifle over so you are looking into the bottom of the mag well.
    4, Using a feeler gauge measure the gap that is between your bolt head and bolt carrier.  If you lack a feeler
        gauge you can use one or two pieces of paper, though a feeler gauge is needed to obtain a proper measurement.
    5, If you have less than .3mm of gap than you will need to acquire + size rollers which are available on the G3 page of this website.  Then
        follow the instructions for the above topic titled "how to remove rollers" and replace your rollers.

Q: What Replacement parts should I purchase for my HK?
A: this is a hard question to ask so I made a page for it: G3 Replacement Parts List  ...Info for Cetme Rifles too!

Q: How do I replace my cocking handle or cocking handle spring?
A: 1, Field strip your rifle, removing buttstock and bolt assembly
        2, With the rifle field stripped pull back the cocking handle to the farthest back position.
        3, There is a round hole in the cocking tube, line that hole up to the pivot pin on the cocking handle support.
        4, Using a punch drive out that pin, with the pin removed the cocking handle and spring will fall out.
        5, Most important step after you have replaced you handle or spring prepare yourself to be slightly frustrated. Take a deep breath
        6, If you have not installed a cocking handle before you will find this to be quite tedious!  The spring and handle have to go in a certain way or it wont work.  Take your time and play with it until you get it correctly.  The second time you do this it will be easy, but the first time it might be difficult.  Just take your time and it wont be a problem.

Q: How do I clip and Pin a Lower?
A: I don't know!  I have never done one myself.  I use a gun smith that is listed on our links page.  This modification can be done by the home gun smith but I can't tell you how.  Check online at Cetme Rifles or HK Pro if you want to do this yourself!

Q: Does my rifle have an old style, or new style triple frame?
A:   Depends on which type of cocking tube you have.  If your cocking tube is strait all the way into the triple frame / front sight assembly than you need the early style triple frame.  If your cocking tube tapers at the end just before the triple frame than you need the later style.  The early style has an extra part that the handguard pushpin rests on.  The later style tapered tubes use a hanger that the pushpin goes into.

Q: How do I remove or install a Barrel?
A: Call a gun smith!  This is not an easy task.  Consult a good HK gun smith.

Q: What does a Port Buffer do?
A: Port Buffers do three things
    1, Protects the finish of your rifle near the ejection port
    2, Protects good brass from being destroyed during the G3's violent ejection process
    3, stops brass from flying as far.  If shooting at a puplic range

Q: How does the Port Buffer attach?
A: The buffer clips onto the top of the receiver and the rubber buffer ends up at the rear of the ejection port.

Q: Can the Port Buffer and Low Profile Scope Mount work together?
A: Yes! The the low profile mount is designed to work with the port buffer installed. You can install everyting as pictured here: Picture

Q: Does a Port Buffer work on a Cetme?
A: Yes! The port buffer works on the Cetme, HK and G3

Q: Does a Carry Handle work on a Cetme?
A:  Yes, however you have to slightly modify the hand guard of your Cetme.  The Carry Handle can work on all Cetme's and G3 Clones

Q: Can I use a HK Stock Set on my Cetme?
A: Yes!  You might have to slightly reduce the size of the recoil rods "Guide Ring" but HK stock sets will work perfect on your Cetme. For pictures and more info on this visit www.cetmerifles.com

Q: How to install a Wide Forearm on my Cetme?
A: Wide forarms can work perfect on a cetme but require a small amount of fitting.  Check out www.Cetmerifles.com for pictures and info

Q: Does a HK Rear Sight work on a Cetme?
A: Yes & No!  You can use a HK rear sight on your Cetme but first you must install a HK rear sight base onto your Cetme receiver.  We have new rear sight bases in stock and they must be welded to the receiver.

Q: Which HK parts work on a Cetme?
A: Click here: RTG Parts CETME-HK Compatability page

Q: How can I tell if I have a Cast or Stamped receiver?
A: Info/Pictures can be found on Cetme Rifles

Q: Do all HK Parts fit my FA91 with the giant aluminum receiver?
A: No, Yes & Maybe: No outer cosmetic parts will fit due to the increased size of the giant aluminum receiver. This includes the collapsible stock, wide handguards, port buffers, carry handles Etc. Accessories that attach to the receiver do not fit unless modified by you. All small internal parts like extractors, rollers, triggers, Etc work fine. Just use common sense: If the part is built to attach to the thin HK steel receiver it will not fit the giant aluminum receiver on your FA91. If it's internal parts you need. They will fit perfectly!

Q: How do I fold and HK Receiver Flat?
A: Hey guys I am not qualified to tell anyone how to do this. I am not a gunsmith and have not tried this myself. That said we have had hundreds of customers who manage to do it at home and there rifles tend to look great. There are HK discussion forums (like HKPro.com) where you can ask advice on this subject. If I was going to fold my own receiver I would start by searching out useful information on HKpro.com. Search past posts for this subject.

Q: How is the quality of POF Parts?
A: Excellent.  We are very proud to offer a small selection of POF parts.  Hopefully this selection will continue to grow in the months to come.  The POF small arms factory was set up by HK.  All procedures and techniques were set up by HK and are maintained to this day.  All tooling is HK made and HK serviced..  All blueprints are HK licensed.  Materials such as steel and plastic all come from the same German companies that supply HK.  Materials are shipped from Germany to POF, and now are shipped from POF to the USA.  Testing and Quality control is as set by HK and is followed precisely.  POF metal parts offer perfect functional quality and currently serve dozens of militaries on five different continents.  Plastic parts are rugged and strong and have a good fit and finish.  Plastic molds were produced by HK.  POF is constantly working to improve quality.  In the past functional quality was always perfect but cosmetically POF parts lacked in comparison to HK.  In the last years POF has concentrated on improving cosmetic finishes and this last shipment of POF parts is the best we have seen.

Q: What condition are the Surplus parts in?
A: Excellent or better condition unless otherwise stated.  The grade excellent is taken from the NRA grading scale for surplus military parts.  Every part sold by RTG parts is hand check by Me to ensure the parts are complete and in perfect working order.  Some parts might have finish wear but no metal loss or damage.  The parts we sell will work perfect and will serve you and your rifle well for years to come.  That said if you are ultra picky and want mint/new than you should really buy new parts.  Some of our parts are new and will be stated as so on our website.


I will be adding to this page as new questions come up.  If you have any suggestions for new topics please send me an email.  I will try to update this page often.
Thank You
Robert Johnson
RTG Parts

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This page was last updated June 16, 2008