FPS dropped from 0.8J ot 0.68J?

LOOKHERE

Went airsofting 5 weeks ago, my JG AKS47 was firing at 0.8-0.85J, went last week and it dropped to 0.68J, any ideas on why/ how to boost FPS/Range?

Any and all ideas appreceated

thermo

LOOKHERE wrote: »

Went airsofting 5 weeks ago, my JG AKS47 was firing at 0.8-0.85J, went last week and it dropped to 0.68J, any ideas on why/ how to boost FPS/Range?

Any and all ideas appreceated

are you sure your using the same weight ammo? simple things first.
next clean the barrel.
how are you at stripping the gun? you could remove the gearbox and spray silly-cone(:)) in the air nozzle and run the gearbox and spray a bit more in every so often, just spray small ammounts, while you have her stripped you could check the hopup rubber, that there is no rips.

defenderdude

Edit- sorry I'm too slow. Thermo already posted this above.

Really might depend on how it was downgraded in the first place... Any ideas?
If it's a cylinder drill job - might be a bit of work but worth trying the old reliable silicone into the nozzle trick first. Could be due to a poor cylinder/piston o-ring seal.

Basically if you can take the upper receiver off and spray silicone oil into the nozzle, hold it against a rag and see if there's much s..t coming out when you dry fire it. Repeat it if necessary, stick it back together and re-chrono!

Its something i was shown by the one and only legend that is Richie (masada) from eirsoft and I've done it with a few of my guns and been amazed by the results.

Worth a shot before you start surgery... Hope it helps.

c28omzk7ihsxv0

I have a feeling you left the spring half cocked from firing in full auto. This would leave the spring half or fully compressed over time weakening the spring. Just my .02c

T4RGET

-BB weight
-something gave way just with the last shot the last time you had it out, unlikely but it's airsoft so it's possible :P
-the spring was compressed when put away, which should get the FPS back up near enough the same after a bit when it resets it self
- and I wouldn't spray silicon oil into the gear box, bad idea. I was told anyways

Inari

T4RGET wrote: »

- and I wouldn't spray silicon oil into the gear box, bad idea. I was told anyways

Silicone oil won't do any damage to the gearbox...it's just a poor lubricant, so there is no point in oiling gears etc, as you'd have to do it after every skirmish, whereas grease lasts much longer.

Squirting silicone oil through the air nozzle just helps lubricate the piston head O-Ring, creating a better air seal which bumps the FPS. On gear that's a good few months old, when the FPS drops it is normally just the piston head O-ring drying out.

Leftyflip

You have to spray it into the gearbox though... You know, that cylindery bit where the piston thingy is?

LOOKHERE

Can one of you please explain the spring theory in simpler words please? Is is a permanent fix? BB weight is .20, always was and always will be

thermo

it means you may have left the gun with the spring in a compressed state in your gearbox, weakining the spring.

LOOKHERE

And how do I extend it/ bring it to normal size? (never took apart the gun btw)

Hande hoche!

Couple of shots on semi automatic.

MonkeyGuy

Semi-auto won't fix the problem, it just prevents it. Take the spring out and manually stretch it (highly discourage you from doing this) if you're sure it's the spring, buy a new one.

Leftyflip

Mountains out of molehills...

Silicone oil. Inside air nozzle.

Steo_123

Most shops cut springs to lower the fps when they import them instead of replacing it so after the first few thousand shots it loses power because it was cut you will need a new spring.

Inari

Steo_123 wrote: »

Most shops cut springs to lower the fps when they import them instead of replacing it so after the first few thousand shots it loses power because it was cut you will need a new spring.

When my M249 was firing too close to the button (0.99J), I cut 1 or 2 coils off of the spring (can't remember which), which brought it down to 0.94j, and have since put through thousands and thousands of rounds...as you'd expect given the fact it is a support gun. It has not even come close to dropping in power

To be honest, I've never heard of springs losing power after a few thousand BBs due to a coil or two being snipped - the vast majority of the time, a drop in FPS is an air seal problem i.e. a squirt of silicone oil through the air nozzle, and firing the gun. No gearbox opening required

Steo_123

Inari wrote: »

When my M249 was firing too close to the button (0.99J), I cut 1 or 2 coils off of the spring (can't remember which), which brought it down to 0.94j, and have since put through thousands and thousands of rounds...as you'd expect given the fact it is a support gun. It has not even come close to dropping in power

To be honest, I've never heard of springs losing power after a few thousand BBs due to a coil or two being snipped - the vast majority of the time, a drop in FPS is an air seal problem i.e. a squirt of silicone oil through the air nozzle, and firing the gun. No gearbox opening required

The guy that repairs all the guns at the site i go to explained this to me.

Leftyflip

Steo_123 wrote: »

The guy that repairs all the guns at the site i go to explained this to me.

Sad to say he's wrong. The structure of the spring doesn't change, it merely gets shorter. Cut and finished correctly (cut square, filed flat and smooth), you will not lose any power over time. Cut incorrectly (cut at a sharp angle) is where complications arise, the spring digs into the spring guide or piston and snags up. In a good set up, the spring rotates every time it gets decompressed releasing any torsion. If it digs into the spring guide or piston, it cannot rotate and over time it will be under so much stress it will break, causing a drop in power, gearbox failure and general badness.

I have two set ups in which I needed to cut a spring, the lowest spring I could find (M85), had both of these set ups at 335 when built. I took off a few coils and they have since chrono'd consistently at 320 over the past 4 months with thousands of rounds gone through them.

maciek87

When being cut - always do so on the spring-guide end (on non-liner springs, one end has 5-7 tighter coils for spring guides).
Never saw spring 'breaking' (I mean, springs don't crack in half just like that, even when cut), but from use it can become softer (use of material).

Every spring over time will loose 0.0? % of 'power' - the effect over time is very small though, but still may have influence on the chrono reading.

Sometimes,on improperly cut springs, the sharp edge of the spring works like a drill - it gets in the ball-bearing spring guides in the depth of even 3-4 coils. For that reason, in some cases, there`ll be drop in power, and possibly severe damage to gearbox elements (ie, ball-bearing from damaged spring guide will shatter gears etc.), hence I do believe in ''drop of power because the spring was cut''.

And if you really, really have to cut the spring - as lefty said - file flat the cut-end, and than use anything you have to bend the coils together (so that first coil will sit on the spring guide/piston, instead of sitting on the angle on sharp or filed down edge of where it was cut).

c28omzk7ihsxv0

Inari wrote: »

When my M249 was firing too close to the button (0.99J), I cut 1 or 2 coils off of the spring (can't remember which), which brought it down to 0.94j, and have since put through thousands and thousands of rounds...as you'd expect given the fact it is a support gun. It has not even come close to dropping in power

To be honest, I've never heard of springs losing power after a few thousand BBs due to a coil or two being snipped - the vast majority of the time, a drop in FPS is an air seal problem i.e. a squirt of silicone oil through the air nozzle, and firing the gun. No gearbox opening required

Yeah from a few coils but a lot of the shops have to cut like 5 or 6 which means the piston doesn't always make a full cycle. It can ruin your AOE (Angle of engagement for the gears and the piston) too. At least that's what I heard.

maciek87

Some ''techis'' cut the spring in 3 or 4 bits, and than stick them together on the spring guide... And repairing damage done by that is always Fun:(
I saw that couple of times, and had to show to customers as well (to justify the need of replacing half of the gearbox), hence I`m not suprised by rumors going around...