"Airbrake" piston heads in AEGs, worth it?

[paulwes83]

Hey all,

I'm doing an AK DMR build and saw the option of "airbrake" piston heads. I'm considering trying it out as I know a lot of the spring sniper rifles have them, but I've never really seen an AEG with one. I'm going to be slapping in a pretty strong spring, m140/150.

My main concern is lowering the stress on the gearbox as the piston assembly meets the cylinder head. Normally, I'd just throw a sorbo pad in there, but if I don't have to then I'd rather not. I just feel that an airbrake system, if it does what it's adverstized to do, would be a better choice for gearbox longevity.

I could very well be wrong though...thoughs?

[Spike]

Why would you not want a sorbo pad? It makes AoE adjustment a breeze.

[iKliiu]

A V3 shell is strong enough to handle the M150, all you really need is a sorbo pad.

[Drakker]

I plan to do something similar to what you are doing. I have ordered two plastic airbrake piston heads from Lee's Precision Engineering (http://www.leesprecision.co.uk/). They are not very expensive even when converting to CAD$, shipping was incredibly cheap and fast (5 days or so).

Now, I didn't have time to install one in my M4 yet, but I did install one in my A&K spring SVD, and although I cannot tell you anything about durability and timing in full auto AEG, in my SVD it made an incredible difference in sound level. It went from louder than an AEG to about as loud as my TM VSR10 G-Spec, without using a sorbo pad. The FPS was exactly the same as with the Prometheus piston head I had installed in there, which was quite a surprise. I had expected some loss of FPS, but it looks like the SVD cylinder has more than enough air volume to handle the airbrake.

I will be testing one in my M4 in the next few weeks. My main worry is that it is going to have pre-engagement of the piston and gears because the airbrake slows down the piston, but I plan on using torque gears and a torque motor to reduce ROF and prevent this.

[paulwes83]

The reason I don't want to use a sorbo pad is that it wears out over time and I just don't want the hassle of having to rip the old one off, clean the cylinder head and attach a new one.

Drakker, that's exactly the one I was going to buy except I was going to go for the aluminum one. The shims they provide seems like a solid bet to correct AOE without a sorbo pad and likewise, I'm throwing in torque gears and a torque motor. Good to know that it changed the noise report of your AEG too, cause that's a big bonus.

I guess I'll just have to see if pre-engagment becomes an issue, but as a DMR I don't think it will be an issue. Airbrakes make no sense for high rate of fire.

[lurkingknight]

2 years in my p90 and the sorbo is still going strong... scatterplot 70D without neoprene. There's probably about 50-60k rounds through the p90 now. It has a few marks in it from the piston head.. but nothing is cut.

Put neoprene onto it and you probably won't have to worry about the piston head cutting it apart at all... take some care and countersink the ports in your piston head and properly round them and remove the burrs and you'll have no issues ever.

[ThunderCactus]

Ive made an airbrake for an aeg before
It doesnt work unless you shoot once every 5s
I can go into detail but in short its a bad idea

[paulwes83]

Cool, thanks all. I guess there's a reason why the manufacturers aren't using them in their stock builds except for bolt action airsoft guns. Sorbo pad it is!