G&P M4 Hop-Up issue

[tim25]

Hello, this may be a noob question. If so,please pardon my ignorance.
I bought an G&P M4 9mm conversion off of airsoft extreme back in June. However the mid cap they sent me didn't work. AEX did not send me a new magazine although the magazine was clearly internally and externally damaged. I now just was able to order some new magazines. (Money has been going to home care.) I'm sorry about the back story but I just wanted you to see my frusteration with Airsoft Extreme.
But to the new issue.

I was abble to fire the gun for the first time today!!! I was shooting about 20 yards with iron sights. There was maybe a 2 inch lattern. But when I went to play with the hop-up the dial barely moved. (Also the action didn't open up the chamber... *long sigh*) I don't know to much about G&P. Is the G&P hop-up just an "on/off" style or is there something wrong? Thanks everyone for reading this and hopefully some light to this issue.
Sincerely, noob 7493.

P.S. I heard G&P hop-up kinda sucks. When I was asking questions about this gun, gimpalong said G&P M4 internals are TM compatible. Would a TM hop-up be the best buy for a hop-up system?

[snafu]

I think the g&p Hopup is pretty decent for starters but I would replace the bucking if you feel comfortable with it. I don't know my head from my ass when it comes to gearbox work but I'd like to think I'm pretty good at tuning a Hopup, they're really easy to work on you just want to have a nice work surface so you don't lose any tiny parts. There are many options for a good bucking. Lots of people swear by Prometheus purple buckings. I personally have not used one but I've had good results with a madbull blue and most recently a g&g green bucking. I think what these buckings I've mentioned have in common is they are all a "soft" type bucking which seems to give the nubbing a better and more consistent contact with the bb's. If you do decide to do some work to your Hopup their should be some decent step by step guides on YouTube.

Also the Hopup on your g&p is not an on/off design. The adjustment wheel should have arrows indicating up or down. Are you saying you cannot open the ejection port when you pull the charging handle?

Edit. You should pull apart the upper and lower receiver. Then you can just slide the barrel and Hopup right out. Make sure when you do that the spring on the front of your Hopup unit doesn't fall off and disappear. The reason I suggest this is its the best way to clean your barrel and it will get you more comfortable breaking you gun in two. One you have the barrel and Hopup out you can look down the barrel and see what it does as you dial the Hopup up or down. It's possible you have it all the way off or on. Usually the sweet spot is somewhere in between.

Edit x2. Is your gun front or rear wired? If its front wired pulling the upper and lower apart will not be as easy as I just said.

[tim25]

Could you explain what bucking is? In contrast of the hop up unit. I actually found out how to take the barrel and hop up off. (I bought a g&g or jg m4 that was broken, but it had a prommy barrel that I wanted and also the ris.) They are both wired to the front. So it was a pain. I just was extremely careful.
Also about the action, it won't open the chamber (where to adjust hop up) but I can manually open it with my finger nail.
About the hop up issue is that it barely moves. Maybe an 1/6 of a rotation clockwise and counter clock wise. So there is barely any room to adjust the hop up.

[TheEnd]

The bucking is the rubber sleeve that seals against the nozzle and provides the friction to back spin the bb. It goes over the end of the barrel that is inside the hop up unit.

Aug 7, 2013 20:56:21 GMT -5 tim25 said:

..but it had a prommy barrel that I wanted.

Did you swap the barrels? Sometimes people install the barrel upside down in the hop up. This causes the nub to press against the top (bottom actually) of the barrel and causes the hop up dial to hardly move. There is also the side effect of no hop up. Pull the upper off and pull the hop up out and look down the chamber end. Try adjusting the hop up. If you don't see the top of the bucking moving it has to come apart to figure out why. The barrel has a square cut out on one side and a groove cut in the other. The square should go on top and the groove should be on the bottom. The bucking will have a raised section that goes into the groove.

I haven't had very good experiences with G&P hop up chambers and I have read a bunch of similar experiences on other forums. Mine just haven't performed very well. Before you replace it I would recommend trying to fix it first. If the barrel is upside down a new hop up won't fix it.

[tim25]

I never put the prommy in yet. I never did anything but put some silicon lube in it and shoot it. I was thinking about just putting a new hop up in just for a performance enhancement. Thank you for the help too. I'll have to check it out when I get out of work tomorrow. To tired to fine tune things right now. I'd get frusterated.

[tim25]

OK I think I figured this out. I partially took the upper receiver off. (Wiring to the front has a protective coating. It couldn't fit through the gap.) But then I fiddled with the hop up... to my surprise it worked. So I put the receiver back on. Test it again. Did not work.... but I figured out that the front wiring was jammed between the dial and the wall of the receiver. I believe it works now.
New problem. Taking the receiver off... this receiver is much better put on than that jg/or g&g I mentioned earlier. I have to slide it all the way off. But that coating won't let me. I guess I'll have to carefully peel it back some. Also Ill try and report if the hop up does work. Its a the blue gear model. But sadly I won't be able to truly test it until this weekend. I'll just report back in a couple of days.

[TheEnd]

Aug 7, 2013 21:54:27 GMT -5 tim25 said:

I never did anything but put some silicon lube in it and shoot it.

Don't put silicone oil in your hop up. The hop up system uses friction between the rubber bucking and the plastic bb to generate the back spin. If you lube the rubber you get no friction and no hop up. I would highly recommend you remove the bucking (or have a local tech do it) and wash it in warm soapy water to remove the silicone. If you can't do that at least use your unjamming rod and some soft cloth and try to wipe it off.

Is the coating on the whole wire, or is it the heat shrink at the end? I can't remember ever working on a front wired G&P so I never encountered your problem. Sometimes you need to pass one connecter through at a time since the heat shrink on both is too thick. I can't see G&P forcing you to rewire just to get the upper off. Can you take a picture?

[ctres]

Most likely there is a heat shrinked connector somewhere up front in the handguard that you can disconnect and snake through the little opening to allow the upper to slide off. I personally hate front wired AR varients because of the hassle it is to take them apart.

[Brush]

Aug 8, 2013 19:43:38 GMT -5 TheEnd said:

Is the coating on the whole wire, or is it the heat shrink at the end? I can't remember ever working on a front wired G&P so I never encountered your problem. Sometimes you need to pass one connecter through at a time since the heat shrink on both is too thick. I can't see G&P forcing you to rewire just to get the upper off. Can you take a picture?

The connectors connecting the gear box to the battery/fuse whip have heat shrink on them. Each connector is shrink wrapped, and then they are shrink wrapped after being connected. In order to separate the upper completely from the lower, you have to cut the first layer of heat shrink to disconnect the wires. They will not fit through otherwise.