marcusr

G&G have released this on their youtube channel: It looks like a very interesting new hop design - I don't like the external adjustment requiring a screwdriver but locking to the front of the gearbox could improve air-seal.

Just by looking at the position of the piston through the cylinder port while firing in full auto. I'm looking for the piston to be temporarily stationary after slamming forwards. I assume with PME the piston is caught by the sector gear while still moving forward and therefore never stops moving. I don't have the video from yesterday or access to my kit right now, but here are some I took a few months ago before all these upgrades. The second one is in full auto: https://imgur.io/a/cNyhP4o

So for anyone else asking a similar question in the future, I've got the empirical data. I shot 20 times before and after shaving off 2 teeth, with the spring/barrel/cylinder combo from my post above & both with no hop applied. I've got pretty excellent air-seal/consistency and based on the spread and standard deviation of the shots this wasn't negatively impacted during the upgrade (not that it should be by gears, but there's always the possibility of not putting it together quite as well as I did last time). Before the average was 332.7 fps and after is 302.2 fps. Little more than I'd like off the power, but I'm getting no PME on full auto and a super-slo-mo video shows it's close enough to the point where I'm better off safe than sorry! Once I've got the hop adjusted properly and measured the power again, I might get an M120 spring to make up the difference.

Ah that's good to hear. I'll go for 2 teeth off and report back here to report the results for others to know for the future.

Hi all, I've recently made some significant improvements to the air seal in my G&G CM16 SRL and the FPS has jumped from 314+/-7 up to 332+/-2 with 0.25s. I would like this to be down at 305-310 for my local field limits. I am about to put in some 13:1 gears as well and intended to shave teeth anyway to avoid pre-engagement, so it fits well with my goal to reduce power! My main question is how many teeth should I remove (I was thinking 1 or 2?) to get the power I want, however there is a slight complication. Part of the air seal upgrades was adding an R-hop, and in doing so I have obviously installed it with zero hop applied and tested like this. I don't have anywhere to shoot it until I go to a game so I can't go and test properly in the garden to dial-in the hop adjustment. So with that in mind, the slightly more complex question is "how many teeth should I remove given that I currently have no hop applied at 332 but will at the field when I want it to be 305-310?" Other relevant factors: M110 spring 380mm barrel 4/5 cylinder Thanks in advance!

Bought full compression kit (rocket cylinder head, zci cylinder & piston, gp pom piston head) and the gears, then attempt an r-hop. Big upgrades incoming!

I think I'll replace the compression parts and teflon tape up the hop-up. Inner barrel is 380mm and I the cylinder looks to be about 2/3... I know that isn't a category that exists but it doesn't look like 3/4.

It's the gearparts M110 from your site, and had about 3000 rounds through it, so pretty new. I get +/- 5fps between shots so I think I might need to fix air seal. Got the stock compression parts apart from air nozzle.

Hi ak2m4, love your site! I get ~310 with 0.25 and ~345 with 0.20, so just within my site limits. Does this suggest air seal issues?

Ah so I'm using an 11.1v 1500mah 15C battery - don't know where that sits on the battery spectrum. I also forgot that there's an M110 spring in there which could be relevant.

Hi all, I'd like to make some upgrades and want to know if I'll need to make other alterations. I currently have a G&G CM16 SRL. Only relevant gearbox changes are a high torque (22 TPA) motor and a sector delayer chip. I'd like to swap out the stock gearset for a 12:1 or 13:1, but I'm concerned I'll cause pre-engagement and need to shave a tooth off the sector gear. I don't currently have the tools available to do so. Does anyone have a similar set-up and know if this is likely to cause pre-engagement and piston wear issues? Thanks

Just wanted to say thanks guys, the delayer chip has sorted the issue completely, even with the slightly faster motor I've installed.

Oof that's not great. What do you all buy and where from?

I have the SRL. It has three screws (one on each side and one underneath) that attach the handguard to the octagonal block underneath. Easy to see in this video, skip to 1:40. Unfortunately it doesn't look like it would fit on your predator, sorry.

Alright thank you I'll try the delayer. I'm already using what I think is decent ammo.

So if I take out the hop unit and barrel, hold it upside down, and drop a BB then it gets caught on the end of the bucking (I assume that is the feed lips?). If I push on the BB with a screwdriver it fairly easily falls into the barrel. Should I try to grind down the end of the bucking or could I ruin air-seal?

Thanks for the reply Skara! I didn't actually measure the original nozzle, I just bought this one as it said it was an M4 one and a cursory look online suggested anything from 21.3-21.5 would be fine. I will take it apart again and see if the problem goes away with the stock nozzle. I'm hesitant to go back to it because I've seen a significant FPS and consistency improvement with the new nozzle so would rather solve the issue. The gear delayer sounds like a great idea, would something like this be appropriate? This is the hop rubber I am using. I bought it recently after I ruined the previous (identical) one attempting a flat-hop, and actually installed at the same time as the new nozzle, so maybe I should investigate there too.

Hi all, new to the forum, started airsofting again recently after a 5+ year break. I've had some problems with my AEG since I made some simple upgrades. I have a G&G CM16 SRL with the following changes: ZCI barrel ZCI aluminium rotary hop unit Maple leaf bucking & nub ZCI air nozzle The problems only arose after I recently opened the gearbox to shim/grease and replace the air nozzle. The hop and barrel upgrades have been around for a while with no issues. Basically in semi it shoots better than ever, but now in full auto it only shoots an actual BB about 50% of the time (not every other shot, just at random). I would have assumed that it would be the new air nozzle being slightly too long or something, but it shoots 100% of the time in semi so that makes me think the nozzle should be fine? I took a slow motion video of the nozzle moving in semi and full auto. Based on the fact that the piston is stationary after each shot during auto I assume it can't be pre-engagement. I do notice that the nozzle might not be retracting as far in auto. Please let me know if there are any other videos/pictures I can take (in or outside the gearbox) to assist. I'm basically asking if anyone has any ideas for what's wrong, and how I might go about fixing. Thanks in advance for any help!