Sturm Posted January 25, 2017 Report Share Posted January 25, 2017 My GHK M4 has an RA Tech receiver (SDP) with Colt markings. As I have heard, the default dust cover does not work correctly on it, and that is also correct in my case. The GHK dust cover will not close with the bolt forward. If the bolt is held back, it will (generally) be able to stay closed, and will open when the bolt is released. So, wary of this, I purchased the RA Tech 'New Age' dust cover. I hoped it would work, and after installing it today, it does not 'work' correctly, but does its job a bit better than my previous GHK one. The dust cover does not stay closed with the bolt closed, like the GHK one, but will close with the bolt locked back successfully, and stays shut very firmly. Why is this? Do I need to file anything to get the dust cover working? It was a giant bloody pain in the *albatross* to install, so I am hoping my efforts have not been in vain. Video: I would also like to mention that I installed the dust cover through the removal of the delta ring assembly, which required an armourer's tool. I did not thread on the delta ring the entire way because doing so *fruitcage*ed the gas tube hole alignment. Is this normal? I show it for a second or two in my video. Does it look trashy? I did not remove the roll pin holding onto the gas tube in the front sight block, so that might have complicated things a bit in aligning the gas tube with the hole in the upper receiver, whilst still threading all the way down. Link to post Share on other sites
renegadecow Posted January 26, 2017 Report Share Posted January 26, 2017 The bolt carrier appears to be too far forward relative to the receiver. The scallop on the side is a relief for the catch on the dust cover to fit in. With it forward it no longer fits in the proper space. In fact, it's only supposed to touch the front end of the scallop which is what forces the dust cover open. I did not thread on the delta ring the entire way because doing so *fruitcage*ed the gas tube hole alignment. Is this normal? I show it for a second or two in my video. Does it look trashy? I did not remove the roll pin holding onto the gas tube in the front sight block, so that might have complicated things a bit in aligning the gas tube with the hole in the upper receiver, whilst still threading all the way down. Link to post Share on other sites
Sturm Posted January 26, 2017 Author Report Share Posted January 26, 2017 The bolt carrier appears to be too far forward relative to the receiver. The scallop on the side is a relief for the catch on the dust cover to fit in. With it forward it no longer fits in the proper space. In fact, it's only supposed to touch the front end of the scallop which is what forces the dust cover open. And is there anything I can do about that? Someone else told me that it could be that the GHK bolt notch that the dust cover latches into is not deep enough, and when used in conjunction with an RA Tech receiver (which I am), it is different enough to keep the dust cover from closing. That being said, the New Age dust cover is much more study when shut with the bolt locked back than the default GHK dust cover (which had a 50/50 chance of staying shut with the bolt back, and was very sensitive to even the slightest pressure or force). That seems to me like the receiver is not really at fault, nor is the dust cover, but perhaps the bolt? Would an RA Tech bolt carrier possibly solve the problem? I notified Airsoft Taiwan about this and they said they would look into it and get back to me. Link to post Share on other sites
renegadecow Posted January 26, 2017 Report Share Posted January 26, 2017 Easy enough to find out. Pull the bolt back a few mm so the dust cover catch is right about centered to the scallop in the bolt. If it still fails to close shut then the relief really is too shallow. You can try grinding down the surface of the lock bit by bit but don't let the bolt slam into it full force until you polish the ground surface or it'll scratch up your bolt. Link to post Share on other sites
DarkLite Posted January 26, 2017 Report Share Posted January 26, 2017 If you've not screwed your delta ring in all the way, your barrel could be sitting too far forwards, causing the bolt to sit too far forwards, causing the issues you are having. Also, you could, being in the US, just get a real steel dust cover. Link to post Share on other sites
CaptCalvin Posted January 26, 2017 Report Share Posted January 26, 2017 I did not thread on the delta ring the entire way because doing so *fruitcage*ed the gas tube hole alignment. Is this normal? I show it for a second or two in my video. Does it look trashy? I did not remove the roll pin holding onto the gas tube in the front sight block, so that might have complicated things a bit in aligning the gas tube with the hole in the upper receiver, whilst still threading all the way down. You need to tighten the barrel nut first and foremost. And yes it's normal. In fact it's rare to get perfect alignment first try. People generally torque it incrementally within the torque range, back it out torque it again, and after a couple of tries the threads get worn in enough to where you'd get good alignment. If this doesn't get you enough progress there are also indexing shims to give you additional control over how the barrel nut indexes when you torque it. Look them up. Link to post Share on other sites
Sturm Posted January 27, 2017 Author Report Share Posted January 27, 2017 If you've not screwed your delta ring in all the way, your barrel could be sitting too far forwards, causing the bolt to sit too far forwards, causing the issues you are having. Also, you could, being in the US, just get a real steel dust cover. I hoped that would be the case. It isn't, however. I took everything apart (again), and literally tightened the barrel nut as tight as it would physically go. If I could even turn it tighter without either my arm breaking, or the armourer's tool bending, the threads probably would have ended up getting stripped anyway. So, that is not the problem. Dust cover will still not close. Could it just be the GHK bolt detent is not deep enough to catch the dust cover latch? Keep in mind I am also using an RA Tech forged receiver, so I think that probably plays a role (I believe its specs are more closely aligned to a real M4 receiver than the GHK one is). Should I pair the RA Tech receiver and dust cover with an RA Tech bolt carrier? Do you think that would do the trick? Link to post Share on other sites
Sturm Posted January 27, 2017 Author Report Share Posted January 27, 2017 You need to tighten the barrel nut first and foremost. And yes it's normal. In fact it's rare to get perfect alignment first try. People generally torque it incrementally within the torque range, back it out torque it again, and after a couple of tries the threads get worn in enough to where you'd get good alignment. If this doesn't get you enough progress there are also indexing shims to give you additional control over how the barrel nut indexes when you torque it. Look them up. I did everything over and tightened right to the end of the threads. It is actually very solid now. The only 'problem' is, if I ever need to take the delta ring assembly off for whatever reason (I really hope not), I'm going to have a hell of a time turning the barrel nut, even with the armourer's wrench. It is literally machine tight now. https://imgur.com/a/3l7e2 Link to post Share on other sites
CaptCalvin Posted January 27, 2017 Report Share Posted January 27, 2017 The original barrel nut design isn't meant to be taken off and put back on on a regular basis. Every time you torque it you change how it indexes. The idea is you endure the headache and frustration until you get everything right once, and then you leave it alone. Link to post Share on other sites
Batmause Posted January 31, 2017 Report Share Posted January 31, 2017 I also have an RA-Tech receiver. We tried to test with different dust covers with any good results. That receiver is a ..... We also had a lot fitting and tolerances issues too. Miss-drilled trigger guard pin hole, miss-drilled forward asssit pin hole, I can fix the barrel with the "delta ring", the stock/GHK bolt carrier all the time stuck/jam, the bolt carrier has an offset with the barrel extension / hopup unit and that is why the feedinglips/nozzle/BB often break. RA-Tech did what they do all the time. They promise a good product which cause a lot trouble for a lot money... Link to post Share on other sites
Sturm Posted February 1, 2017 Author Report Share Posted February 1, 2017 I also have an RA-Tech receiver. We tried to test with different dust covers with any good results. That receiver is a ..... We also had a lot fitting and tolerances issues too. Miss-drilled trigger guard pin hole, miss-drilled forward asssit pin hole, I can fix the barrel with the "delta ring", the stock/GHK bolt carrier all the time stuck/jam, the bolt carrier has an offset with the barrel extension / hopup unit and that is why the feedinglips/nozzle/BB often break. RA-Tech did what they do all the time. They promise a good product which cause a lot trouble for a lot money... I think my receiver is one of the new 7075 aluminium versions: https://m.facebook.com/SDPAsia/photos/ms.c.eJwzNzcytTAwM7M0NTMwsDDVM4fwzY0sLI1NDC0AZoIGZg~-~-.bps.a.772580662893419.1073741843.359026760915480/772580669560085/?type=3&source=48 It also does not have the issues that I've been told many of the 6061 RA Tech receivers had. The lines on the front of the upper and lower receivers are aligned properly as well. Anyway, I am waiting on my RA Tech bolt carrier to arrive. I also bought the Samoon enhanced buffer tube and buffer spring. In the meantime, I realised that my rear takedown pin is missing its spring and detent. It originally had it, but they slipped out and I believe I threw the spring away, since I had no idea what it was for. It does not cause any issues, besides the fact that I need to drive the rear pin out with a hammer and punch for disassembly, which is a pain in the *albatross*. It has always been like that, even when I first got the rifle. I just assumed that the rear takedown pin did not have the captive ability that the front one had. I was wrong. I ordered a new rear takedown pin from Samoon as well. My receiver appears to be using the RA Tech New Age front and rear takedown pins, so I'll just need the rear detent and spring. How do I install it properly? Link to post Share on other sites
DrAlexanderTobacco Posted February 1, 2017 Report Share Posted February 1, 2017 I believe I threw the spring away, since I had no idea what it was for. Link to post Share on other sites
Sturm Posted February 1, 2017 Author Report Share Posted February 1, 2017 I might have not. Honestly, I cannot remember. I know for a fact though that I kept the detent. I originally mistook it for a broken bit of a punch that previously had snapped off. Anyway, how would I reinstall the spring and detent? Any tips? I know it has something to do with a hole under the plate holding the stock in place. That is all I really know, however. Link to post Share on other sites
QQexDERA Posted February 1, 2017 Report Share Posted February 1, 2017 Undo the nut on your stock tube and screw it out by 1/4". Pull the stock plate back, rotate stock tube a few degrees then pop the detent and spring in place. Reverse the procedure. If the castle nut is on really tight, then pick up a cheap armours tool instead of attempting to bodge the job. Far less chance of damaging anything by accident then. **edit** If the nut is done up tight enough that you need to use the armourers wrench, then hold the lower receiver in a vice by the stock tube (or, to be more accurate, by the spine underneath it). Do NOT hold the receiver itself in the vice. Link to post Share on other sites
Sturm Posted February 1, 2017 Author Report Share Posted February 1, 2017 Undo the nut on your stock tube and screw it out by 1/4". Pull the stock plate back, rotate stock tube a few degrees then pop the detent and spring in place. Reverse the procedure. If the castle nut is on tight, then pick up a cheap armours tool instead of attempting to bodge the job. Far less chance of damaging anything by accident then. I already own an armourer's tool. What part of it is used to undo the castle nut? Would I have to remove the buffer tube pin thing (piece that holds the buffer tube in place)? Any order? Is it detent first, and then the spring? Any side that the detent needs to be facing? Link to post Share on other sites
QQexDERA Posted February 1, 2017 Report Share Posted February 1, 2017 You're looking for the part of the armourers wrench that looks a bit like a C spanner. As to order, put the rear receiver pin in place with the slot in it towards the rear, then push the detent into the receiver followed by the spring. Link to post Share on other sites
Batmause Posted February 6, 2017 Report Share Posted February 6, 2017 blablalba Our receiver was ordered from RA-Tech directly. The receiver haven't any pin detention as your don't have. The receiver has different pin size as the GHK has and for me, the receiver was drilled with different size - as I remembered, 6mm for 6.2 pins. It was the last time when I bought metal body from RAT, next time I'll cut my hand off if I do it again... Link to post Share on other sites
Sturm Posted February 8, 2017 Author Report Share Posted February 8, 2017 Time for an update! So yeah, I finally got the RA Tech bolt carrier, and I installed it earlier tonight. I also installed a Samoon buffer and buffer spring (the default buffer spring is quite weak, especially considering the GHK's steel bolt). It was a pain in the *albatross* to get that damn c-clip piece of *suitcase* back on again to secure the nozzle return spring (I also needed to replace the black oring, as it swelled so much that it literally broke in half). So, with the RA Tech carrier, the dust cover functions completely as it should. That is what I was wanting, and I am very pleased about that. However, I also have some concerns. The RA Tech bolt carrier is quite 'stiff' and has a lot of resistance when pulling the charging handle. It often feels very tight in the upper receiver. In addition, despite being brand-new, small edges of the extreme top and bottom portions of the bolt have lost a bit their parkerised / phosphated finish. Is this all normal? Do I just need to allow the carrier time to break itself in? I have noticed in particular that the 'tightness' when the bolt is in battery is because the bolt's piston head (or whatever it is called in this circumstance) seems to take a lot of pressure to seat fully in the hop up chamber. Should I stop acting like a freak and give the thing time to work itself in? https://imgur.com/a/0b2xL Link to post Share on other sites
Sturm Posted February 8, 2017 Author Report Share Posted February 8, 2017 Oh yeah, and I forgot to mention that I reinstalled the detent thing. It turns out the detent spring had never fallen out, but was stuck inside its hole! Anyway, I think I did it right. I still need a hammer or mallet and punch to get the pin out enough to take the receiver off. This is in contrast to the front takedown pin, which a lot of times can simply be pulled out by hand (with appropriate force). Is the rear takedown pin made to be harder to remove than the front takedown pin? Also, the stock is a bit misaligned. Just a small tad. I'll need to line it up straight again. What is up with the bolt carrier? It is pretty smooth up until the nozzle assembly makes contact with the hop chamber, and then it becomes very tight. Is there any reason(s) for this? Just simple break-in? Link to post Share on other sites
QQexDERA Posted February 9, 2017 Report Share Posted February 9, 2017 Surface finishes wearing off are pretty common in Airsoft - it's just down to low quality. Some companies even manage to combine low quality materials with surface finishing!With regards to having problems getting the rear receiver pin in and out, if you're having to really wail on it with a hammer to move it then check for distortion and burrs of both the holes in the receiver, the lug on the underside at the back of the receiver, and on the pin itself. If you've distorted the holes in the upper or lower receiver then run a reamer through them. If the rear pin is distorted or burred then file/sand to shape, or just get a new one. Have a particular look at the slot that the detent pin rides in as well. As to the bolt carrier, sounds like the fit between the nozzle assembly and the barrel extension could be the problem. Can you see wear marks on the nozzle assembly? Link to post Share on other sites
CaptCalvin Posted February 9, 2017 Report Share Posted February 9, 2017 Is the pin getting bound even without the receiver closed? Also as a general rule of thumb the moment you start putting in RA-tech BS your gun turns instantly turns into a money sink. Link to post Share on other sites
Sturm Posted February 9, 2017 Author Report Share Posted February 9, 2017 Surface finishes wearing off are pretty common in Airsoft - it's just down to low quality. Some companies even manage to combine low quality materials with ###### surface finishing! With regards to having problems getting the rear receiver pin in and out, if you're having to really wail on it with a hammer to move it then check for distortion and burrs of both the holes in the receiver, the lug on the underside at the back of the receiver, and on the pin itself. If you've distorted the holes in the upper or lower receiver then run a reamer through them. If the rear pin is distorted or burred then file/sand to shape, or just get a new one. Have a particular look at the slot that the detent pin rides in as well. As to the bolt carrier, sounds like the fit between the nozzle assembly and the barrel extension could be the problem. Can you see wear marks on the nozzle assembly? The bolt carrier is acting much better now. I would actually say it is almost as the old carrier was before (in terms of fitment). It is hard to tell for sure though, since I upgraded the buffer tube and buffer spring with the Samoon kit. Seems a lot more responsive though, and the gun functions, so that is good (lol). About the rear takedown pin, it certainly is held captive by the detent and detent spring. However, it always needs a hammer or rubber mallet and punch to remove. The front takedown pin, on the other hand, can (usually) be grabbed and pulled out by hand (obviously not completely, since it is held captive by the detent). I do not know if this is by design or not. The rear takedown pin hole on the lower receiver is a bit burred near the left edge, but it does not prevent removal or insertion of the pin at all. If anything, it probably makes it easier to get the pin seated properly (since the edge has a minor resemblance to the hollow side of the takedown pin). Link to post Share on other sites
QQexDERA Posted February 10, 2017 Report Share Posted February 10, 2017 Some of them can take a sharp tap to move them, but you really shouldn't have to give it a good beating with a hammer! Link to post Share on other sites
Sturm Posted February 10, 2017 Author Report Share Posted February 10, 2017 Some of them can take a sharp tap to move them, but you really shouldn't have to give it a good beating with a hammer! Well, that is usually what it takes. True, I probably am putting more into it than I need to. A good strike with a hammer would likely move the rear pin in enough to just get it out the rest of the way with just a punch, but I just use the hammer the entire way. Oh well... Link to post Share on other sites
Beeingmyself Posted March 22, 2017 Report Share Posted March 22, 2017 Sorry for hijacking but I can't seem to find the original GHK M4 thread - anybody? Link to post Share on other sites
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