M120 Spring questions

[Villid]

What is the typical velocity range of an m120 spring?  and would i need to upgrade my internals to run one, or would stocl JG internals be capable of handling the new spring?

[SteevoLS]

The number after M is meters/second. Multiply that by 3.28 and you'll get the rough FPS with a .20 BB.

M120 = 393.6 FPS. Realistically, you'll get somewhere around 390-410.

An older JG can take a 120, but you will see internal failures start to crop up before too long. 2010 JGs are a bit of an unknown, though. They've been revamped, but I don't know to what extent. In general, expect to see piston or gear failures when you start putting in higher springs.

[Vesper]

If good compression, an M120 spring will put out the velocity between 380~410 FPS.

If your gun shoots less than 360 FPS with an M120 spring an .20 gram BBs, then you might want to take a look at the compression.

[Villid]

i chronoed right around 310 this past weekend, and ive the spring laying around so i fiugred id try it out.  what is typically the first part to fail?  the piston?

[SteevoLS]

Most likely the piston would strpi, given that it is designed to be a failure point. As with all things airsoft, though, it can really be a crapshoot.

[Vesper]

Just about anything can break. You have to remember, it's airsoft.

Just keep in mind that sometimes, breaking points are where you least expect.

[Gabe]

In a JG, I think your safest bet would be to leave it alone unless:
1-It's an experiment or loaner/backup gun
2-You're planning on upgrading it further anyway
3-You just want to see how much it can take before breaking

I bought a haul of JG 552's last year and took every single one of them apart, most down to the gearbox.  To my knowledge, they were '09 models, and this is what I found most of the time:
1-The wiring sucks.  Consider replacing even if you don't plan to upgrade.
2-The motors are loud at pretty much any setting (even after shimming), but they do have decent power for the price.
3-The safety is only a physical cutoff, not an electronic one like TM.  For some reason they bypassed the gap normally closed by the selector plate.  The wiring is already about as thick and durable as wet toilet paper, so you may as well replace the trigger unit too.
4-Two out of my 10 had a unified spring/piston like stock TM's.  The spring isn't irregularly pitched, and the piston head isn't ported.
5-All but one had a plastic spring guide...nuff said about that
6-None had metal bushings...once again...nuff said


Anyway, if it were a simple yes or no question, I'd say no unless you really just don't care if it breaks.  As for the FPS, everyone beat me to the punch, and I agree with the above statements.  Make a note however, that MadBull uses .25's to rate their springs, so a Madbull spring will be significantly stiffer than a different brand.  I can vouch for their performance, my Sig 556 still shoots about 450, and it's been about a year or so since I put that spring in.

[Villid]

In a JG, I think your safest bet would be to leave it alone unless:
1-It's an experiment or loaner/backup gun
2-You're planning on upgrading it further anyway
3-You just want to see how much it can take before breaking

I bought a haul of JG 552's last year and took every single one of them apart, most down to the gearbox.  To my knowledge, they were '09 models, and this is what I found most of the time:
1-The wiring sucks.  Consider replacing even if you don't plan to upgrade.
2-The motors are loud at pretty much any setting (even after shimming), but they do have decent power for the price.
3-The safety is only a physical cutoff, not an electronic one like TM.  For some reason they bypassed the gap normally closed by the selector plate.  The wiring is already about as thick and durable as wet toilet paper, so you may as well replace the trigger unit too.
4-Two out of my 10 had a unified spring/piston like stock TM's.  The spring isn't irregularly pitched, and the piston head isn't ported.
5-All but one had a plastic spring guide...nuff said about that
6-None had metal bushings...once again...nuff said


Anyway, if it were a simple yes or no question, I'd say no unless you really just don't care if it breaks.  As for the FPS, everyone beat me to the punch, and I agree with the above statements.  Make a note however, that MadBull uses .25's to rate their springs, so a Madbull spring will be significantly stiffer than a different brand.  I can vouch for their performance, my Sig 556 still shoots about 450, and it's been about a year or so since I put that spring in.

The gun im gonna put it in is my primary weapon, but was free, so if i break it, no real financial loss there.  I was lucky enough that mine did have metal bushings, so its got that going for it.  When i do install this, im gonna aslo be putting in a polycard piston of some kind(currently readnig up on metal teeth and the pro/con of them), a metal spring guide, and stock KWA motor.  assuming the gears hold together, and i dont see why they wouldnt at only a 120, it should hold up for a while.  my trigger contacts are already becoming an issue, so thats on my future upgrades list

[Gabe]

Depending on the ratio, your gears should be ok, but once you go M120 and above, you want to at least consider getting torque ups.  Even if you have gears that are impossible to break, if the ratio isn't high enough, your motor will start to struggle.

[Villid]

yeah, that was the main reason i was switching from the JG motor to the KWA motor.  figured it would be a little more reliable

[gonzo]

All good advice.

I'll second what Vesper said, though.  Before you touch anything else, check your compression.  Most AEGs ship with terrible compression.  Putting a layer or two of teflon tape around your cylinder head, and properly greasing your nozzle and piston o-ring will go a long way towards boosting your fps.  If you can put your finger over the nozzle and still depress the piston, your compression is bad.

If you want to go for just raw spring power, like everyone above me has said, something will break.  My guess is that since it's a JG, even before the piston strips, your cylinder head will disintegrate.  Which sucks.  Cylinder heads aren't terribly expensive, so if you really want to go witch the stronger spring, that's what I'd recommend changing first.  The piston would be second, but a close second.

My advice, though, is pull it apart and do a number on the compression.  Tips on this are really easy to find, and it's something that's very easy to fix.

[Vesper]

Just for an advice, these items are what I put in my Combat Machine M4 in order to upgrade the spring to an M120.

G&G M120 Spring
G&G Upgraded Piston
G&P M120 Ultra Speed Motor

Those 3 items alone can put down ~25 BPS with a 9.6v battery at ~380 FPS. and they all can be found on AirsoftGI's website.
Compared to other upgrading process, I suppose this is rather cheap.

PLEASE do make sure that your gun's compression is at the best condition. With good compression, you can put out up to 400 FPS with just an M120 spring.