Upgrade, new gearbox or new gun?

Lozart

Lozart

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My aging TM M4A1 is suffering. Greatly. At a game Thursday night it chrono'd at a whopping 232 FPS on 0.2s. Now granted I can tweak the hop to get a bit of range out of it but seriously - I'd like at least SOME muzzle velocity!

So the question is (being a relative newcomer to the internal machinations of the thing) am I losing air pressure somewhere (and if so how do I actually tell), do I need a new spring (which will involve taking the gearbox apart and quite possibly it never working again) or should I just buy a complete new gearbox (bearing in mind that I could actually get a whole new gun for not much more)?

If I go the new gearbox route - what makes will fit into a TM M4A1 and which should never be fitted inside anything other than a large round waste recepticle?

If I go the spring route, how much else will need replacing (bearing in mind an ABSOLUTE top limit of 340FPS)? I'd rather have a decent rate of fire than shedloads of FPS to be honest.

 
providing all the bits inside are still functioning (should be, gears especially will be fine) get a guarder M100 spring and that's all you'll need. A whole new gearbox is massive overkill for what's probably just a spring that's lost it's springyness.

other possible causes are poor air seal;

piston o-ring could have died,

nozzle could be cracked

Your piston could have lost a couple of teeth, which would cause the gun to 'short stroke', but this is unlikely given the low power spring that's been in there.

Best bet is to open it up, the V2 gearbox isn't all that bad, just make sure you keep all the bits!

 
Cheers for that.

How would I tell if I have a poor air seal?

If I'm opening up the gearbox anyway does anyone do an "overhaul kit" or somesuch fro a V2 gearbox? With seals and stuff?

 
Get a cheapo bag of o-rings from ebay, shouldn't cost more than a couple of quid, gears won't be a problem. Poor air seal you can test by trying to manually depress the piston while holding your finger over the nozzle, if it's easy then there's something likely wrong, if it goes in a couple of mm and stops you're probably alright.

 
Cool. Cheers for that.

For the price of the bits I'm probably going to look at a new nozzle and piston O-ring along with the spring.

I mean.....what's the worst that can happen? :)

 
Train_wreck_at_Montparnasse_1895.jpg


 
Why not get a new gun anyway? You will feel more confident stripping your old one down, knowing you have a spare at the ready. Xmas is coming up so start dropping hints :D

 
Just out of interest, what condition is the hop rubber in?

 
Russe11 said:
Why not get a new gun anyway? You will feel more confident stripping your old one down, knowing you have a spare at the ready. Xmas is coming up so start dropping hints :D
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I'm planning on a G&G SCAR-L around Xmas anyway but I still need something to use in the meantime. The gun was cheap but old and in need of a bit of TLC anyway.

 
sp00n said:
Just out of interest, what condition is the hop rubber in?
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Nearly new. Changed to a TBB a couple of months ago and swapped out the rubber then. I also have a Dytac metal receiver set to fit to allow me to change to a single piece hop so it'll get a new rubber then as well (I'll most likely do all the work at the same time - so I won't have a clue which bit isn't working anymore, as one does).

Having bought the gun cheap second hand I'm using it as my "learn how it works by slowly wrecking every part of it in a ham fisted attempt to produce the most leet n00b pwning machine EVARRRRR!" project. It's basically like Triggers M4 now. Once the receiver goes in the only original parts will be the pistol grip, the gearbox, buffertube and outer barrel... :)

 
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sounds a lot like my old Marui M4, still worked fine after a few tweaks and I got £200 for it!

 
Not sure if I'll ever sell it to be honest. I'm hoping to mutate it as my play style changes (it is indeed an old Marui M4A1 just like yours) and keep it as a backup.

 
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