Let's Unfuck a Brand New Action Army T-11: a Build Log in Case Anyone Wants to Make a 1j Build Out of This Thing

[Skara]

It's been quite the rollercoaster with the new spring yesterday.

Installed, first shot on 0.2s gave me 0.9J, good, loaded some 0.4s and BOOM, 1.4J. A whopping half Joule of creep on a 300mm inner.

Then removed the solder from the piston, 109/110 m/s with 0.2s and 1.56J on 0.4s....

Put the stock plastic piston in for science, 1.6+ joules on 0.4s, didn't bother with 0.2s.

The fuck.

Started cutting coils and got it down to 1.38J on 0.4s before nipping the spring too short to hold everything under tension (to prevent the spring guide stopper from falling off).

Wasted a spring, ordered a M100 now.

So it appears that the whole heavy piston best piston is a bunch of bollocks.

I can only see it being used to cheat the chrono at those sites where chrono is made on FPS/0.2g.

 

[Adolf Hamster]

I can only see it being used to cheat the chrono at those sites where chrono is made on FPS/0.2g.

i must admit, if there's a benefit other than that i'm not 100% sure what it is.

unless forcing the piston to impact slower is better for noise? although i'd have assumed a lighter piston would be easier to slow down.

 

[Skara]

i must admit, if there's a benefit other than that i'm not 100% sure what it is.

unless forcing the piston to impact slower is better for noise? although i'd have assumed a lighter piston would be easier to slow down.

I thought it was supposed to let you use a lighter spring to achieve the same energy level as a stiffer spring + lighter piston combination but it's not true (at least in my case), all it does is reduce the pressure spike on light bbs, because the amount of JC stayed the same at +0.5J (0.9/1.4, 1.05/1.55).

Sound wise, it's the airbrake's job to slow down the piston before it hits the cylinder head pad, we already established that on my setup it doesn't work.

Good news is Pavol (SCW guy) is willing to make me a dedicated airbrake for my cylinder head (I'll send him the exact measures tonight).

As of now I'm not too worried about having a quiet gun, main concern is the power output

 

[Adolf Hamster]

I thought it was supposed to let you use a lighter spring to achieve the same energy level as a stiffer spring + lighter piston combination but it's not true (at least in my case), all it does is reduce the pressure spike on light bbs, because the amount of JC stayed the same at +0.5J (0.9/1.4, 1.05/1.55).

i thought it'd be the opposite, more kinetic energy in the piston means you're gonna need more initial spring energy. but the momentum of the heavier piston then limits the velocity the bb can acheive regardless of its weight because the bb's energy gain is a smaller proportion of the energy in the system.

come to think of it, it's really hard to describe how i think the whole heavyweight piston thing works.

 

[Skara]

Either way, with my setup a heavy piston is not needed other than chrono cheating purposes

M100 spring went in yesterday, it clocks at 0.94J on 0.2s and 1.25J on 0.4s, with an intermediate 1.15J on 0.3s.

Better, I guess, still running hot for my limit but I'm not gonna do anything until the new airbrake is installed.

For a brief moment, though, I accidentally got the current airbrake to work:

During testing the gun suddenly became whisper quiet (not quite mk23 levels, but surely inaudible over 5 metres), at first I thought something in my internal suppression had moved out of position and was blocking the barrel, but BBs were flying straight and at a consistent velocity (eyeballed). Chrono readings were just 0.1J below the "loud" results, so I started to take the gun apart.

Noticed some PTFE coming out of the nozzle, that's when I realized the airbrake jacket I made with PTFE and heat shrink had come off the airbrake and got stuck in the cylinder head, making the stock 4mm airbrake perfectly functional

I have removed it now, but fuck me sideways it was dead quiet!!!!!

Still have to test the sound from the target's perspective but if everything goes according to plan, I'll end up with a 0.99J gun that is stupid quiet without having to cut the spring  at that point I can call the build done from a mechanical point of view and start working on camouflaging it (without ruining the pristine looks with spray paint or other shit).

 

[Skara]

Pavol just sent me this picture

Fucking humongous airbrake to match the ML cylinder head  should be here in 10 days or so

 

[Adolf Hamster]

there's gotta be a joke in here about expanding girth.....

 

[Skara]

there's gotta be a joke in here about expanding girth.....

There are more rock hard phallic shaped objects in my gun than in pornhub or something ?

 

[Adolf Hamster]

well expanding the girth so it's a nice tight fit is gonna keep her quiet at least.

 

[Skara]

Will she cope with the pressure?

cuz that's a whole lotta shaft in her hole

 

[Adolf Hamster]

Well you're not slamming it in there too hard, so should be fine.

 

[Skara]

Airbrake delivered, size comparison to a €2 coin (26mm diametre)

If it works the build is complete and I can start working on camo

EDIT:

It appears to be working, the gun is noticeably quieter, the energy output is unchanged, 1.1J on 0.3s, 1.3J on 0.4s, but I blame it on the bearing spring guide I installed as well, I might go back to the stock plastic one until the spring settles in.

Won't test it this sunday as I want to try the AEGs first and I need to work on a camo wrap.

Maybe next sunday