Sewdhull

Well at 60 fps the nozzle to bucking relationship is losing the air. I'm assuming all else is well.
 
So your options are worn or broken tappet plate, nozzle or bucking. Nozzles get wear inside and at the tip whacking the bbs all the time, tappet plates wear on the fin and buckings get worn lips...
 
Inconsistent air seal issues often fall to the nozzle and bucking meeting offline due to wear and then things get gradually worse. If a bb always comes out that's where I would start and just replace both the nozzle and bucking with the same thing as is there already.

ok, the UV leds i was looking at were I think, 3.5 fV so 4 of those, even 3 would be under or around battery voltage in series. Looks like yours are parallel tho so you'd need the current limiters.
LED drivers are cheap, so that's another possibility.

Corrosion,
 
Stainless or brass, Stainless if there's got to be a winner 

Yes it has IR function. Chargers haven't got better in a long time, so there's lots of good ones out there. Cabling is often an issue but if all your batteries have the same plug it won't matter. XT60 for the win.
 
If you test the battery when new, fully charged, then test occasionally will see the battery decline over time.
Useful for comparing know good batteries to any new ones you get.

I test all the batteries I buy and return the crap ones.
I don't worry about capacity if the IR is low. Give and take...

Other than the plug and it fitting, there's no Airsoft battery as such.
You can imagine that batteries, even small ones that supply more than a hundred amps regularly need to be 'better' than a battery putting out 40.
I use Amazon batteries and some nano techs and whilst youd notice it on a drone in a gun you don't.
 
I'll charge all mine up, leave them a day and see what the rof is and put a new post up. Maybe I'll have my super dooper lion battery made by then.

If this is happening after the gun has been working fine then it's cut off lever wear most likely, maybe trigger trolley. The contacts don't have a way to close up over time, only open wider. 
 
If it were me, I'd get a new cut off lever and set of contacts ( they cheap). With the gearbox together still you can see the operation of the lever and trigger trolley and see how the cut off lever behaves, but it is this lever tipping the trigger trolley that gives you semi when the sector gear flips the trolley up.
 
If the contacts look good, just replace the trolley and leave the contacts alone.

It's the fit really and yes some clips fit better than others at least that's been my experience. I have used a little epoxy to pad out the clip so it has no play, but you need to carefully align stuff and then let it cure. In short, I roughed up the barrel flats, degreased em, then put a little epoxy on the flats and put the clip on. Once the epoxy firms up take the clip of and use a knife to tidy the excess. In a perfect world id put the epoxy on the clip but it doesn't adhere as well to the clip as the barrel.
 
If the barrel and bucking are moving together you can shim the bucking to the hop with PTFE tape. Also make the front part of the hop snugger onto the barrel (where the ring goes in if you have one)
If the barrel is moving inside the bucking you can shim the front part of the bucking to the barrel and make the front part of the hop snugger as above.

It's the fit really and yes some clips fit better than others at least that's been my experience. I have used a little epoxy to pad out the clip so it has no play, but you need to carefully align stuff and then let it cure. In short, I roughed up the barrel flats, degreased em, then put a little epoxy on the flats and put the clip on. Once the epoxy firms up take the clip of and use a knife to tidy the excess. In a perfect world id put the epoxy on the clip but it doesn't adhere as well to the clip as the barrel.
 
If the barrel and bucking are moving together you can shim the bucking to the hop with PTFE tape. Also make the front part of the hop snugger onto the barrel (where the ring goes in if you have one)
If the barrel is moving inside the bucking you can shim the front part of the bucking to the barrel and make the front part of the hop snugger as above.

When I get home I'll measure what a gas fill wieghs on one of my mags.
 
Likely to be at room temp the gas so should fill well.

The only corrosion that's blue I know of is that of copper.
But it could be ground up thread lock
 

You need 800+Celcius to anneal springs, stainless is higher.
 
The 20FPS loss is because the spring is less pre compressed, there's no extra friction in having 1 bearing instead of 2. I'm going to explain why because it's come up before.
 
If you compress a spring one end will rotate with respect to the other and if you have a bearing at one end, that end will rotate freely because bearings have less friction than the spring rubbing against another flat surface and once the bearing is rotating there is not enough force to rotate at the other end. The whole spring is not rotating, the wire is repositioning itself as it is put in torsion, so if it is fixed at one end the other rotates.
In Airsoft we have bearings not for friction issues, but so that the spring maintains its shape and does not bend to one side or the other when it gets compressed. You could fix the spring at both ends and have no frictional losses but you would still have the spring deforming as it compresses.
 
If you put a bearing at both ends and lets say, one bearing is a bit stiffer than the other, then the bearing with the least friction will rotate first, but the other bearing will not rotate because the force to rotate it never gets high enough since it is relieved by the first bearing to rotate. This is essentially what happens if you have just one bearing.
 
 Remember that if the spring is fixed at one end there are no frictional losses, as it doesn't move.
 
Friction also doesn't care about area, only the force and coefficient of friction. So if you have a bearing at both ends the friction is double that of one bearing, since the force at both ends of the spring is the same. If only one bearing rotates, the friction is halved. Because the angle the spring rotates is double with 1 bearing the same amount of losses occur. Both bearings need to rotate of course for this to be true.
 
 

You need 800+Celcius to anneal springs, stainless is higher.
 
The 20FPS loss is because the spring is less pre compressed, there's no extra friction in having 1 bearing instead of 2. I'm going to explain why because it's come up before.
 
If you compress a spring one end will rotate with respect to the other and if you have a bearing at one end, that end will rotate freely because bearings have less friction than the spring rubbing against another flat surface and once the bearing is rotating there is not enough force to rotate at the other end. The whole spring is not rotating, the wire is repositioning itself as it is put in torsion, so if it is fixed at one end the other rotates.
In Airsoft we have bearings not for friction issues, but so that the spring maintains its shape and does not bend to one side or the other when it gets compressed. You could fix the spring at both ends and have no frictional losses but you would still have the spring deforming as it compresses.
 
If you put a bearing at both ends and lets say, one bearing is a bit stiffer than the other, then the bearing with the least friction will rotate first, but the other bearing will not rotate because the force to rotate it never gets high enough since it is relieved by the first bearing to rotate. This is essentially what happens if you have just one bearing.
 
 Remember that if the spring is fixed at one end there are no frictional losses, as it doesn't move.
 
Friction also doesn't care about area, only the force and coefficient of friction. So if you have a bearing at both ends the friction is double that of one bearing, since the force at both ends of the spring is the same. If only one bearing rotates, the friction is halved. Because the angle the spring rotates is double with 1 bearing the same amount of losses occur. Both bearings need to rotate of course for this to be true.
 
 

A certain rated spring takes into account the length of the spring to arrive at the strength the spring will be used at.
 
For example you can increase the strength of a spring using spacers to pre-compress it or it can be longer than another spring with same spring constant which ends up pre compressing it when installed. In fact all the springs seems to have a degree of pre compression when installed.
 
For springs that are the same length they need to be stiffer, thicker wire or some such. Looking at the springs I have what seems to happen is that some springs are just longer than an otherwise identical spring, until you need to use a stiffer material because you'll run out of room to compress it.
 
Springs are cheap enough, I wouldn't bother cutting one. Take off a bearing at the guide end if you have one on the cylinder head perhaps, you don't need 2 bearings.

Ultimately the thing that determines the strength of the spring is the force needed to compress it when installed and compressed in the cylinder.
 
You can have a long weak spring that gets pre compressed on installation and will be the same rating as a short strong spring which gets pre compressed less. They are all of similar length with variations of up to 25mm from those I have.
Then that option is not available to you.
 
It's not the length that matters but how it's used.
I bought a selection of AKs springs when I was trying to get the right fps on the MP5

Do you have a bearing on the cylinder head? If so you don't need the one on the spring guide. I cant recall how much i lost, ill go hunt down the post
 

A certain rated spring takes into account the length of the spring to arrive at the strength the spring will be used at.
 
For example you can increase the strength of a spring using spacers to pre-compress it or it can be longer than another spring with same spring constant which ends up pre compressing it when installed. In fact all the springs seems to have a degree of pre compression when installed.
 
For springs that are the same length they need to be stiffer, thicker wire or some such. Looking at the springs I have what seems to happen is that some springs are just longer than an otherwise identical spring, until you need to use a stiffer material because you'll run out of room to compress it.
 
Springs are cheap enough, I wouldn't bother cutting one. Take off a bearing at the guide end if you have one on the cylinder head perhaps, you don't need 2 bearings.

Yeah time to target will be less with a heavier BB. Clearly at first, 15 to 20m if I recall correctly, the lighter BB will arrive first but the amount of time you are looking at is neglible. Only once the distance increases does time difference become a factor and then in favour of the heavier BB.
Range is dictated by the hops ability to spin the BB and this uses energy so if you keep the same spring etc and try to spin a heavier BB you will lose some FPS but not necessarily any range, but you might.

Are all those bearings the same width? I use some 3x8x3 bearings and they do protrude and the one under the selector plate needed the plate relieving, but yours look wrong. One flush and one not is weird. i think you'll need to open it up again...
 
https://simplybearings.co.uk/shop/Bearings-Deep-Groove-Ball-Bearings/c3_11/index.html?selection=Flanged+Ball+Bearing
 
Select 3mm ID and you'll see 2, 2.5, 3 and 4mm widths.
 
 

A heavier BB will go further and quicker than a lighter one if it has the same forwards energy.
The issue comes when you add hop to impart more of the springs energy to the BB to make it spin in a similar way to a lighter BB which leaves less energy to make it go forward, so it's slower out of the barrel not only because it's heavier, but also because some of the pushing energy got used up getting it to spin.
Normally we would adjust the spring to add some FPS to compensate for the hop rubbing more.
 
Joule creep happens because a heavier BB takes longer to speed up and exit the barrel than a lighter BB so the force acting on the BB can do so for a longer time (potentially the pressure will be higher too). This only works if the lighter BB wouldn't have used all the energy.
 

The reason is that the average speed of the bb is higher if it is heavier. With greater mass the bb slows down more slowly and the force due to drag is less because of the reduced speed from the outset.
 
So you have less deceleration all the time for the same speed (.2 vs .4 is half of the deceleration due to drag of the .2) and more drag for the same energy for the .2, because its going faster and drag is exponentially  increased with speed.
 
The result is that the .2 has a high force slowing a light bb which reduces it's speed much more than the lower force on a heavier bb. The heavy one overtakes the light one in effect and arrives sooner than the light one.
 
The graph above from the Airsoft trajectory project  shows the time and mass relationship.

I'm certain that has nothing to do with the BB weight, sounds more like hop problems.

Sure, on lower power builds the performance increase of using heavier BBs is less noticeable than on higher power builds. Because the Heavy BBs have less initial velocity to conserve better than their lighter counterpart.

But no matter what, if you have a hop that imparts the same relative spin on both the light and the heavy BB, the heavy BB goes farther. It wont run out of magnus effect sooner. It is heavier, heavy things conserve energy better, and as such will spin longer, prolonging the magnus effect, and conserving the muzzle energy for longer making them faster than lighter BBs at any range farther than ~10-20 metres.

The reason is that the average speed of the bb is higher if it is heavier. With greater mass the bb slows down more slowly and the force due to drag is less because of the reduced speed from the outset.
 
So you have less deceleration all the time for the same speed (.2 vs .4 is half of the deceleration due to drag of the .2) and more drag for the same energy for the .2, because its going faster and drag is exponentially  increased with speed.
 
The result is that the .2 has a high force slowing a light bb which reduces it's speed much more than the lower force on a heavier bb. The heavy one overtakes the light one in effect and arrives sooner than the light one.
 
The graph above from the Airsoft trajectory project  shows the time and mass relationship.

Sorry I thought I'd linked.
 
https://www.ak2m4.co.uk/internal-parts/gearbox-tools

I think your chrono is telling fibs. Even if you didn't suffer from mech issues, your still going need a motor with a no load speed north of 60k