I need some ideas for upgrades

[ModernTimes]

58 minutes ago, Colin Allen said:

Cycling a V2 gearbox without securing the spring guide being secured can be disastrous; don't ask me how I know!  It can also make a not insignificant difference to the power.

It is quite easy to make up a collar that you can use to secure it with the screw.

 

1 hour ago, Shamal said:

I see what you mean but as @Rogerborgsaid the buffer tube needs to be attached because the screw that attached it also screws into the spring guide which helps to hold it rigid.

So has the gearbox shit itself?

 

I put the tube back on and this time the spring was fine.

 

304 - 316 FPS with 0.23g bbs and M115 spring.

 

Update:

310 FPS average. 0.91J

Edited July 16 by ModernTimes

[B4by_Dr1v3r]

Ideas:

https://docs.google.com/spreadsheets/u/0/d/1SP0FAw9ytpG-p-mNt8c2po8mVRdOfkdP/htmlview?pli=1

[Colin Allen]

4 hours ago, ModernTimes said:

310 FPS average. 0.91J

310 fps on a 0.23 is 1.02J

[ModernTimes]

14 hours ago, B4by_Dr1v3r said:

Ideas:

https://docs.google.com/spreadsheets/u/0/d/1SP0FAw9ytpG-p-mNt8c2po8mVRdOfkdP/htmlview?pli=1

 

Thanks for this, I'll check it out.

 

12 hours ago, Colin Allen said:

310 fps on a 0.23 is 1.02J

 

How is the Joules calculated in the chronos? Does it use the weight to calculate this? I was under the assumption that weight of BBs was only used in calculating the FPS.

 

My chrono is set to 0.2g BBs and I am testing with 0.23g BBs. Getting a reading of 310 FPS. And before you ask, I can't change the weight because its a chinese cheap model.

Edited July 17 by ModernTimes

[The_Lord_Poncho]

Just run down the left hand side of this table to find the FPS reading that you are getting, and then go across the table until you get to the weight of the BB you are using for the testing.  https://www.airsoftmaster.com/fps-chart-for-airsoft-guns/

[ModernTimes]

2 hours ago, The_Lord_Poncho said:

Just run down the left hand side of this table to find the FPS reading that you are getting, and then go across the table until you get to the weight of the BB you are using for the testing.  https://www.airsoftmaster.com/fps-chart-for-airsoft-guns/

 

It seems even if I change the BB weight on the chrono, the Joules changes but the FPS remains the same.

 

Seems a reading of 310 - 317 FPS with 0.23g BB.

 

Is there any other precautions I should take or anything I should add? I'm pretty happy with it. Just maintenance left now.

[Colin Allen]

5 hours ago, ModernTimes said:

 

It seems even if I change the BB weight on the chrono, the Joules changes but the FPS remains the same.

 

Seems a reading of 310 - 317 FPS with 0.23g BB.

 

Is there any other precautions I should take or anything I should add? I'm pretty happy with it. Just maintenance left now.

FPS will remain constant as you change the weight setting because the chrono reads the velocity of the BB, which has not changed.

 

The chrono then uses the velocity and the set weight to calculate the energy in Joules.

Edited July 17 by Colin Allen

[Rogerborg]

This catches a lot of people out, not helped by some sites still talking in terms of "FPS" when the very next thing they have to say it "... with a 0.2g BB".

 

All chronos measure feet per second (or metres per second) regardless of what you're shooting through them, whether it's a 0.2g plastic BB or a 115 grain full metal jacket 9mm bullet.

 

But what actually matters to the target is the energy of the projectile, which has to be calculated from the speed and the mass.  This is typically measured in Joules, although airguns still tend to talk in terms of foot-pounds, which is also a measure of energy.

 

Legally speaking, what is and isn't an airsoft gun is defined by the energy in Joules, and their insurance policies will use that too.  Talking or thinking in terms of fps is really archaic now, and can actually result in some big oopsie when players turn up with guns shooting "350 fps" but with something like a 0.25g BB, which works out at 1.42J, way over site limits or even the legal limit for an automatic airsoft gun.

 

It's unfortunate and pretty unusual that your chrono can't be set to display Joules based on a projectile weight, but I'd highly encourage you to start thinking in terms of Joules instead of fps, and always testing with the weight of ammo that you intend to use (and for woodland, we'd recommend using the heaviest weight that your wallet and hop unit can stand, I typically use 0.28g)

 

There are plenty of conversion charts available, or calculators that will work it out:

 

http://www.coderedairsoftpark.com/pages/park-rules-and-hours/fps-calculator.php

 

The tl;dr is that if you're shooting 0.23g then the maximum fps you should be aiming for is about 325, which comes out at 1.12J.  For safety's sake (i.e. to not come out hot on the site chrono) you'll generally want to test yourself at about 1.1J, or about 320 fps with 0.23g.

[Tommikka]

On 17/07/2024 at 12:22, ModernTimes said:

 

Thanks for this, I'll check it out.

 

 

How is the Joules calculated in the chronos? Does it use the weight to calculate this? I was under the assumption that weight of BBs was only used in calculating the FPS.

 

My chrono is set to 0.2g BBs and I am testing with 0.23g BBs. Getting a reading of 310 FPS. And before you ask, I can't change the weight because its a chinese cheap model.

 

 

A chrono takes 2 readings of the BB passing it, over a known distance and the time it took to pass between those two known points - giving the velocity 

 

 

Velocity = distance / time

 

(Though to be pedantic that is actually the speed, because velocity includes direction - a chronograph assumes that the object is going in the right direction)

 

Joules are the energy, therefore the mass must be taken into the equation 

Chronos don’t have scales so a calculation is made against a set mass

 

In paintball we make the assumption that paintballs are ‘standard’ and measure the velocity (the general maximum is below the legal energy limit for paintball) and the international standard for paintball goggles includes a maximum velocity in the design as well as the impact limit of the lens itself …. Which includes the breathing holes etc 

In airsoft due to the smaller mass there has always been scope for higher velocities (and then changes occurred on joule limit - if applied to paintball our balls would just about roll out of the barrel)

With the range of different BB weights depending on material specifics airsoft rules get set in joules and therefore should be checked on a case by case basis against the BB

 

 

Therefore paintball chronos are expected to report velocity in FPS and airsoft chronos are either set to convert velocity to energy internally or a reference table is used 

As you’ve noted your chrono has an assumed mass therefore gives you the wrong joules, which means it’s measuring velocity, calculating joules at an assumed mass and then you need to recalculate back from that 0.2gram mass to velocity then apply 0.23 gram to come up with  a corrected energy …..

 

You should be able to divide by 0.2, and multiply by 0.23 (or just multiply by 1.15?)