MGC M4A1 help (merged with M4A1 Jamming)

Hello everyone--I am new to the forum. I could REALLY use an experts help regarding the MGC M4A1 Shorty. I have 2 of these guns, but I can't seem to get them to fire without jamming every round, or every other round. i could also use help with a detailed field strip. i am accustomed to taking the bolt out, but have no idea how to get to the chamber, or the detonator in order to properly clean it. Would someone be so kind as to send me information on theis--I am a visual learner also, so pictures help immensely. I have also taken the bolt apart, and would like help with reassembly--I have reassembled it, but want to make sure the ball bearings and springs are all in the "right" place, and make sure evertything was done correctly. I just can't seem to figure out why the guns won't fire. Please help--thanks so much!!

Trevor.styles@ctt.com

Hello!

First of all, the MGC M4A1 fires quite reliable. Anyway it needs good cleaning. I noticed that mine tended to misfire or jam after approx. 25 - 30 rounds.

Cleaning the chamber and detonator pin is vital. Also the carts have to be clean and the piston (the part with the rubber o-ring) has to move smoothly. Then it should perform okay.

I can't find the time to give you a step by step tutorial right now. I just can't do it as I am ill and have to do some office work anyway.

Are you familiar with the M4/M16 system? To get to the firing pin and chamber do this:

1. Remove handguards.

2. Remove frontsight. Drive the two pins out with a small punch tool (a nail may do too, but I#d file it flat and smooth first). You can slide it towards the barrel end/flash hider. Gastube has to be removed too. Drive the small pin out which holds the gas tube (chromium rod) into the front sight.

3. Remove the gas tube by pulling it out through the receiver (bolt carrier removed).

4. Unscrew the barrel nut by using the supplied wrench tool.

Now you can pull the barrel out of the receiver. You can also pull the chamber and the detonator pin out now.

Be careful when reassembling: Do not damage the brittle HW plastic threads.

Good luck!

Thanks for the reply--I will try my best to follow the instruction--I did not receive a wrench tool with either gun...can I use a large wrench or pliars, or will this damage the gun? Any hints on the bolt reassembly with the ball bearings and spring? I noticed the ejector plate is a bit worn down-the bead has been flattened...can this be a problem? I also noticed the charging handle has a couple cracks at the point where it "hooks"---the hooked end grabs the bolt key. Could this be an issue also? Thanks for the help!!

I'd highly recommend that you get that tool first. It is a special MGC die cast "wrench". Using a wrench or pliers may damage the weak metal of your barrel nut.

Contact forum member Shazhib or Francky in Japan. Both can get you spare parts for good prices. Both will ship to the USA. They are very helpful and trustworthy!

If the round stays in the chamber, it could be an extractor issue.

Did your gun come with a manual? These are in Japanese, but the drawings are very helpful.

Thank you for the help--I asked Francky about the wrench a month ago...and he told me to use a wrench...like the one you use to fix a water pipe...but I will contact him again, and see if he can send one.

As for possibly being an extractor issue, what would I look for? How could I tell if that is it or not? Any "glaring" issues to look for? I did notice that the extractor seems to sit into the bolt a bit far...but I don't know why...the spring and ball bearing are in place.

Thanks for the help Guys--yah Francky is the best--he has been GREAT with me, and really helpful--I'll definitely continue to get my stuff from him!! Is there anything else I should request besides the MGC wrench? any other tools that may be helpful, or possible replacement parts for the M4? Cerwyn gave some tips as far as testing the auto fire function--if it does indeed end up being the Auto Sear, are these easily replaceable? I have heard that MGC went bankrupt and no longer makes parts...this could make getting replacements difficult for this gun. Can parts be made? Anyway--Cerwyn and Mad Mike--I will try your suggestions and let you know how this goes! Thanks again guys!!

one of the problems with this model is the ejector on the bolt it should move freely but after use the edges burr and the ejector fails to move this causes terrible ejection problems and it needs to be removed and the edges filed smooth. be very careful when taking the bolt apart as there are a couple of very small ball bearings and springs which are vital to the smooth running of the bolt which spring out very easily and get lost. Its been a long time since i took the ejector off so cannot remember if you need to take the bolt apart or if you can just take it off and nothing else, also its possible the springs and ball bearings may be missing if the bolt has been taken apart before.

Thanks Claymore for the response--Both Ball Bearings and both springs are still intact. You are correct though--these are TINY pieces that fall out all too easily upon disassembly!! I have filed the extractor down also. The ejector seems a bit tricky, and I am just unsure if it is sitting correctly--I am also unsure if this was the original spring, or if somewhere along the line someone put a different one in...It just seems more "rigid" than it should be. I can send pictures tonight if it would be helpful, to show how I am putting it together--please let me know if this would help. Thank you

Hello everyone-I have been having some problems with jamming issues in my MGC M4A1 Shorty. I have suffered a cracked bolt, but have since super glued it. Here are some of the last test I ran--please read and see if you have any ideas. I would seem that the bolt is "catching somewhere", thus not sliding smoothly, and not going forward enough to put the next cartridge into the chamber, and it is also making the bolt absorb a lot of the energy.

After the bolt crack, the gun is not working on Semi or Full Auto. I ran some tests however. I did manual ejection tests. I noticed that a good portion of the shells were not being extracted from the chamber, and the ones that were would often just fall from the breech rather than get thrown out. So then I noticed the bolt wasn’t closing all the way. I hit the forward assist after each shell was ejected—then it worked perfectly (one shell would eject—hit the forward assist 2 or 3 times, eject the next shell, hit the forward assist…so on and so forth). So I loaded up a full clip. Jam, after jam after jam on semi auto. First round would fire and eject. Pulled the trigger…click. Hammer would go up…no cap fired, nothing. So then I would have to disassemble the upper receiver, so I could push the hammer back down, so I could eject the jammed cartridge.



So then I tested with my “forward assist” theory. I fired the first round, then hit the forward assist. Next round fired (then hit the forward assist), and the next (hit the forward assist), and the next(hit the forward assist. About 90 percent of the clip fired perfectly (on Semi Auto)…IF and ONLY IF I would hit the forward assist once or twice after EACH time the gun fired. I pulled the bolt from the receiver after firing and also noticed that the crack had intensified. The super glue layer was worn away, and the crack was a bit larger, with a small hole in the crack now.



So some questions:

Why would I need to hit the forward assist? Is the bolt getting “caught up” on something? Is there not enough “spring” to send the bolt back into the closed position? Perhaps the bolt face is too tight?
What would make the crack intensify? The bolt assembly must be taking on a good degree of the impact force, when it should not be.


What can I do to test theories, and try to solve this?

THANK YOU EVERYONE!!

If the bolt seems to "stick" in the chamber then it may be because the head of the bolt has begun to widen under the force of the rounds continually pushing into it ...the "star" pattern may be spreading apart ...I`ve only seen this on models that have fired an awful lot of rounds but it does happen ...to remedy you should lightly file the outer edges of the bolt head ...Id avoid trying to squeze the bolt head closed as you may crush it.

certainly if the bolt is catching elsewhere it will give you poor performance too...look for tell - tale rub marks on the bolts outer surface.

DOC

Zinc


Doc

DOC wrote:

Zinc


Doc

Thanks Doc... that's satisfied my curiosity

Thanks for the reply Doc--I do have a streak worn on the side of the bolt assembly from the ejector plate...there is also a "stripe" from wear on the inside of the upper receiver caused from the ejector.