BrightCandle Posted April 16, 2014 Posted April 16, 2014 Gun is G&G CM16 Carbine. The hop up is set all the way to off. At 5m the rounds are in the black on a paper target, however when I go out past about 7m the rounds are landing higher. At 10m I am finding the rounds are 3cm higher than the aim point. Admittedly the spread is also about 3cm's as well but its consistently above the aim point for all rounds. I am assuming this is the hop up doing its thing too aggressively. Should I be expecting a flatter trajectory than that or will it tend to flatten out at longer range as the velocity drops off? Because I can't adjust the sight any lower and I can't turn off the hop up anymore as its off/minimal already. I don't know how this is going to handle at realistic ranges and I seeing as how its dark CQB I wont be able to see during the game where they land.
Unrustle_Thine_Jimmies Posted April 16, 2014 Posted April 16, 2014 Take out the hop up chamber and look down the barrel- If there is a Hop up mound protruding then there might be something wrong with the adjustment mechanism- some G&G CMs did have problems with the hop up just jamming on certain levels though I've only seen it in a few friend's guns.
Mike636 Posted April 16, 2014 Posted April 16, 2014 BB's just like real bullets dont have a truly flat trajectory so 3cm at 10m is pretty good I'd of said. I set my hop up so the BB's get their maximum distance and just aim a bit lower in CQB,
RR01 Posted April 17, 2014 Posted April 17, 2014 10 metres is way to short a distance to zero your sights. You need to zero for at least 40 metres, then hold under for shorter ranges, although when shooting at a man sized target anywhere on the body is a good enough hit for a kill.
dex Posted April 17, 2014 Posted April 17, 2014 Sounds like the hop nub arm is jamming. You may need to take the hop apart and make sure the arm springs back freely. Could be some cack in it. I recently fitted a Lonex hop unit to an AEG and I had to sand a shade off the sides of the hop arm to get it to move freely.
BrightCandle Posted April 18, 2014 Author Posted April 18, 2014 The hop up wasn't stuck, or at least once I got it out and fiddled with it all was working as it should. I took the gun apart to replace the spring to reduce velocity and well now I have the opposite problem, the gun shoots very low and no amount of hop up and sight adjustment corrects it! Sigh. 3 feet low at 10m is a problem.
Supporters Lozart Posted April 19, 2014 Supporters Posted April 19, 2014 The hop up wasn't stuck, or at least once I got it out and fiddled with it all was working as it should. I took the gun apart to replace the spring to reduce velocity and well now I have the opposite problem, the gun shoots very low and no amount of hop up and sight adjustment corrects it! Sigh. 3 feet low at 10m is a problem. Sounds like you've lost way more than your desired amount of FPS. Check your airseal is good.
BrightCandle Posted April 23, 2014 Author Posted April 23, 2014 Looks like the problem might have been nub displacement as it came out when I disassembled again. One thing I do notice with this hop up is that off doesn't mean no nub protrusion, its already sticking a reasonable way out on off. So I suspect that this is the reason the hop up wont disable and why I was getting so much climb before. I am rebuilding with an SHS M90 spring so hopefully that will restore the FPS and get the gun shooting well again but below the requirement and I will have to live with the gun being overhopped, get a smaller nub or get a replacement hop up.
BrightCandle Posted April 23, 2014 Author Posted April 23, 2014 Reassembled hop up and reseated the buckling and with a new spring its about 3cm too high at 10m, which is exactly what it was before the spring change so all is right with the world.
BrightCandle Posted May 4, 2014 Author Posted May 4, 2014 So I decided to see if a H nub would change the situation with my over hopping. So I bought the light and heavy H nub made by element and fitted the heavy one today. With both .20 and 0.25 BB's I seeing less hop being applied by default and the groupings are much more consistent vertically. I no longer get a slight nub protrusion from the outset. The difference in performance is mostly consistency. I could get groupings of about 2.5cm before but they would be higher than the sight and I would get about 4/10 fliers that would be in and around a 8 cm radius, both vertically and horizontally. I tried the same firing test with the H nub and the grouping was 10/10 within the 2.5cm, so all the inconsistent rounds that made a wide pattern are completely gone. At 10 metres I can now shoot through the same hole all day long, its quite incredible. It seems to work a little better with the heavier 0.25 BBs that the 0.2s but it has had an effect on both. Mighty impressed with what is basically 10 minutes of time and a £1.50 for a simple upgrade that makes a massive difference in the spread of rounds landing.
Supporters Lozart Posted May 4, 2014 Supporters Posted May 4, 2014 So was that the white nub or the black one?
BrightCandle Posted May 5, 2014 Author Posted May 5, 2014 I got from land warrior, its a dytac H hop spacer large, I replaced the G&G nub and just stuck it there with some silicon lube. Its black and hard plastic, the g&g nub is a rubber piece with a hole through the middle and just a basic cylinder. I also sealed around the barrel with silicon lube on the bucking and the hop unit as it all went back together. I will try the dytac small h nub at some point but I will want to try this in a game to see what it does at range and what adjustments I will need to the setting.
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