Egon_247 Posted May 22 Share Posted May 22 So.... Having been given a 20+ year old TM m4a1 by someone, Im trying to get it up and running again. Gearbox done, gears, grease n shimming, new piston n m100 spring. All happily doing their thing. Only issue now is that it had a 2 piece hop unit. But alas, one bit was missing along with the barrel. 😕 So I've attacked it with a Dremel and made one fit (an old g&g I had kicking about), bought a barrel too There's no space in front of it for the spring. Upon test firing just now it doesn't feed at all well (1 in 3 shots) but when it does it's up to 0.8j. I get the feeling that the g&g hop unit is crap, it's not a rotary one, so I've ordered a zci one to go in it. Is the spring an absolute necessity? I've heard tales of o rings being used to shim it back to the V2 gearbox. The mag lines up ok but my concern is that if I shim the hop back to the gearbox, the mag won't line up. Any thoughts? Link to comment Share on other sites More sharing options...
Supporters Lozart Posted May 22 Supporters Share Posted May 22 The spring is there to make sure the nozzle seats against the hop rubber properly, that's all. You can definitely use O-rings but they're less forgiving of any magazine misalignment. Egon_247 1 Link to comment Share on other sites More sharing options...
Egon_247 Posted May 22 Author Share Posted May 22 3 hours ago, Lozart said: The spring is there to make sure the nozzle seats against the hop rubber properly, that's all. You can definitely use O-rings but they're less forgiving of any magazine misalignment. Cheers matey. This is the first time I've done a hop unit that wasn't a straight swap. It's sat against the gearbox pretty solid but I'll give the o rings a shot 😁👍 Link to comment Share on other sites More sharing options...
Egon_247 Posted May 23 Author Share Posted May 23 Aha...eureka moment. Looked into the feed tube and the nozzle isn't clearing the tube enough to allow it to feed. Looks like it might be time for a sector delay thingy. Might pull it back far enough to work. 😁😂 Rogerborg 1 Link to comment Share on other sites More sharing options...
Supporters Rogerborg Posted May 23 Supporters Share Posted May 23 5 minutes ago, Egon_247 said: Aha...eureka moment. Looked into the feed tube and the nozzle isn't clearing the tube enough to allow it to feed. Looks like it might be time for a sector delay thingy. Might pull it back far enough to work. 😁😂 Ah, that makes sense, especially if the tappet plate is a bit worn. Thanks for the followup, it's good to hear solutions to the questions. Link to comment Share on other sites More sharing options...
Egon_247 Posted May 23 Author Share Posted May 23 1 hour ago, Rogerborg said: Ah, that makes sense, especially if the tappet plate is a bit worn. Thanks for the followup, it's good to hear solutions to the questions. I just tried a shorter nozzle and it's feeding, just at 0.2j. 😁😱😂 Looks like I need the original nozzle to come back a bit further to clear the feed tube. I wouldn't mind so much but the front wired M4 is a pig of a fiddle to do. 🤬😱😂 Actually, thinking about it, I can't do that cos the tappet plate is held against the cylinder head isn't it? Oh well. Hop unit change. Grrr. Link to comment Share on other sites More sharing options...
Egon_247 Posted May 24 Author Share Posted May 24 Maybe, just maybe, the V3 tappet plate in the V2 gearbox that was installed by the previous owner wasn't the smartest move..... I dunno. Some people....😳🧐 Rogerborg and Herrgh 2 Link to comment Share on other sites More sharing options...
Egon_247 Posted May 25 Author Share Posted May 25 Just a matter of nozzle length now I think. It's still a bit meh. Rogerborg 1 Link to comment Share on other sites More sharing options...
Egon_247 Posted Wednesday at 16:26 Author Share Posted Wednesday at 16:26 This is slowly becoming a wall hanger. Shame really, its a nice pew. Theres no space for a spring in front of the hop unit, o rings wont fit either. the nozzle is clearing the feed tube but i'm not sure its going far enough forward to seal on the hop rubber. Cant remove any material from the hop unit to bring it back further as the mag wont fit.... catch 22.... has anyone actually done this or am i attempting to bring a corpse back from the dead? Rogerborg 1 Link to comment Share on other sites More sharing options...
heroshark Posted Wednesday at 16:38 Share Posted Wednesday at 16:38 The old TM hops had a small spring on a peg protruding from the front of the feed tube iirc. You might be able to recreate it with some ingenuity. Egon_247 1 Link to comment Share on other sites More sharing options...
Egon_247 Posted Wednesday at 16:52 Author Share Posted Wednesday at 16:52 I have a zci rotary in it now. the original was missing along with the barrel. It fits, its tight against the gearbox and the foregrip. it definitely aint moving! I have a concern though. just been doing the googles and it appears that MOST m4 nozzles are 21 point something long. the one that's in it is a 20.7mm. i wonder if the original owner tried to do things and put in the wrong nozzle. I mean, the tappet plate was wrong, so why wouldnt the nozzle be. Ok, back to the drawing board...best go and buy some nozzles... Link to comment Share on other sites More sharing options...
heroshark Posted Wednesday at 16:57 Share Posted Wednesday at 16:57 Ah fair. Always a fiddle with a Frankengun. Egon_247 1 Link to comment Share on other sites More sharing options...
Colin Allen Posted Wednesday at 17:05 Share Posted Wednesday at 17:05 (edited) 12 minutes ago, Egon_247 said: I have a zci rotary in it now. the original was missing along with the barrel. It fits, its tight against the gearbox and the foregrip. it definitely aint moving! I have a concern though. just been doing the googles and it appears that MOST m4 nozzles are 21 point something long. the one that's in it is a 20.7mm. i wonder if the original owner tried to do things and put in the wrong nozzle. I mean, the tappet plate was wrong, so why wouldnt the nozzle be. Ok, back to the drawing board...best go and buy some nozzles... 20.7mm is a long AK nozzle, which matches the tappet plate. Edited Wednesday at 17:05 by Colin Allen Egon_247 1 Link to comment Share on other sites More sharing options...
Supporters Rogerborg Posted Wednesday at 17:53 Supporters Share Posted Wednesday at 17:53 1 hour ago, Egon_247 said: best go and buy some nozzles... This sounds like a job for... https://www.thecageairsoft.co.uk/perun-nozz-x-nozzle-system/ Link to comment Share on other sites More sharing options...
Egon_247 Posted Wednesday at 20:46 Author Share Posted Wednesday at 20:46 (edited) Ooooh. Yeah. Baby. So I poked about a bit more and found that the barrel moved back and forth in the hop chamber, which isn't great obviously. So I cleaned it up with ipa and added a couple of turns of Ptfe tape to the outside of the rubber. Put it all back together and boom. 1.317J on a 0.28g. a touch too high granted but it feeds. It shoots. May have overdone the spring 😁 I'll get some pics up in a bit of it in all it's annoying glory. Thank you guys. Always helpful to those with silly pews...❤️❤️👍😂 Edited Wednesday at 21:19 by Egon_247 ButcherBill, Lozart, Rogerborg and 1 other 2 2 Link to comment Share on other sites More sharing options...
Colin Allen Posted Wednesday at 21:16 Share Posted Wednesday at 21:16 29 minutes ago, Egon_247 said: Ooooh. Yeah. Baby. So I poked about a bit more and found that the barrel moved back and forth in the hop chamber, which isn't great obviously. So I cleaned it up with ipa and added a couple of turns of Ptfe tape to the outside of the rubber. Put it all back together and boom. 1.37J on a 0.28g. a touch too high granted but it feeds. It shoots. May have overdone the spring 😁 I'll get some pics up in a bit of it in all it's annoying glory. Thank you guys. Always helpful to those with silly pews...❤️❤️👍😂 Nice! Well done! Egon_247 1 Link to comment Share on other sites More sharing options...
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