YAY! More CA M15A4 problems (piston snappage, repeated)

[warlock]

Okay, so my M4 is chewing up polycarb pistons. It keeps snapping the back tooth off the piston after about 500 rounds. So, my questions for you fine folks is:

Do I step down the upgrades (high-speed gear set (non-helical), prototype Systema motor (high speed Mk2 I believe it will be called when it is released)) or do I reinforce the top end of the gearbox with aluminum piston, cylinder head, reinforced cylinder....

Should I throw an M120 in? I am still using the stock spring so as not to put too much stress on things, but I fear it might be running a little too fast causing me more problems than it solves.

Of course, with an M120 in, it'll shoot a bit hotter than it is now, and that worries me, as it is shooting straight-up 300fps now....I figured since I was throwing out a ton of rounds per second I'd be courteous to my fellow players and keep the fps down so as not to hurt people. Naturally I could put a pinhole in the cylinder head to take down the FPS a bit (while still retaining the rate-of-fire decrease the M120 would give me...) and bring it down to 300fps again.

I'm just wondering if without the pinhole, figuring a mean average of 25rps, at 340-360fps, would be considered a prick-move by my fellow players. I'm out there to have fun, and I don't want to ruin anyone else's. Not to mention my conscience would kill me if I actually injured someone out there.

So, comments/suggestionss/anecdotes?

[Cheeze_IZ_G00d]

I would reinforce the top end of the gearbox with an aluminum piston. Your rate of fire, and fps will decrease a little bit, so your worry about having to high FPS could be assuaged a bit. You could also go with a ported cylinder, instead of a pin hole in it. It just so happens that I have a HurricanE aluminum piston lying around that I will sell you for 25 bucks.

[azsarge]

Get rid of the High Speed Gears.

DEFINITELY install a silent head set (piston head, cylinder head) and a bearing spring guide.

Make sure you use a ported cylinder for the M4 length barrel.  Some guys use full cylinder, or even bore-ups on short barrels and all it does is slow down your ROF.

If you want to increase ROF, do it electrically, not mechanically.  Get a higher voltage pack, and use std ratio gears and a EG1000 or equivalent.  No high speed motors.

After all, ROF doesn't mean shit if your gun is down!

[Dust2Dust]

You can keep the high speed gears, just get the deepfire piston with all titanium teeth.   And do the rest of what sarge said.

[IcePlatinumSky]

Dude why would you even run high speed with an m120? Your nutz!!! Like Sarge said get a silent head set, Systema spring guide w/bearing, you can use your m120. Get a systema torqe or High torqe gears. Systema original ratio would even be fine. Not sure what motor you said your running in it but a EG1000 or Systema Torque Up motor will work, not sure on the lengh I can remember. Polypiston is great with or without metal teeth. Dont go and get a full metal one its to hard on your Gearbox over time.

Good luck!!!

However, if you wanted high rof rather than fps.  You need different needs.
silent head set, Systema spring guide w/bearing
The current gears you have are fine.
Polypiston with metal teeth
Your spring is ok but you can go up to a 110 or 100
Your motor if its also high speed it may be to fast and an EG700 would be fine.

What battery are you running in this? That causes another problem. If its 9.6 than no wonder.

[KOBO]

Using the same gun, CA M15A4, if I pick up a M120, bearing piston head, cylinder head, and a bearing spring guide, will I be able to leave everything else stock? - Joseph

[Vince]

Probably. I would get bearings too though.

Then, down the road, get Systema gears.

[warlock]

Dude why would you even run high speed with an m120? Your nutz!!!

Mostly bcause I am snapping the back tooth off of my pistons....figured if I got a higher spring, ROF would go down, less stress on that back tooth.

Like Sarge said get a silent head set, Systema spring guide w/bearing, you can use your m120. Get a systema torqe or High torqe gears. Systema original ratio would even be fine. Not sure what motor you said your running in it but a EG1000 or Systema Torque Up motor will work, not sure on the lengh I can remember. Polypiston is great with or without metal teeth. Dont go and get a full metal one its to hard on your Gearbox over time.

Good luck!!!

However, if you wanted high rof rather than fps.  You need different needs.
silent head set, Systema spring guide w/bearing
The current gears you have are fine.
Polypiston with metal teeth
Your spring is ok but you can go up to a 110 or 100
Your motor if its also high speed it may be to fast and an EG700 would be fine.

Looking to go after a high ROF. I don't want to hurt people, I want the ultimate in spray-n-pray weaponry.

Ordered the Matrix piston with Titanium teeth today, should be here early next week. Already have the Systema spring guide with bearing. Will try to step down the motor (would the stock one be a sufficient step-down, or should I aim lower....)

What battery are you running in this? That causes another problem. If its 9.6 than no wonder.

The battery is a Gonzo-built 37A 9.6V 3200mAh custom monstrosity of a nun-chuck. Gonzo rules.

Should I ask him for an 8.4V version of it? Will all this downgrading get me back to a stock rate of fire? Should I just throw all the stock parts back in, and give up on building an M4 that strikes fear into the hearts of the wicked?

I am getting tired of working on it repeatedly, whilst my top-secret sniper rifle goes unattended (and as a result unfinished...). The last upgrade I did before it started eating pistons for breakfast was a new wiring harness, installed by the fine folks at JT Tucson; the one right before this was the upgraded Gonzo battery; prior to that, I put in the fluid bearings, the prototype motor, and the new cylinder head. Prior to the battery upgrade, all was running smooth. We had a training op and I had that thing firing continuously with no issues. I do not know if the battery or the wiring harness is the culprit since (stupidly) I did not put a ton of rounds through the weapon with the new battery installed to make sure things would be copacetic.

I agree with Sarge that a high ROF doesn't mean squat if the weapon is down; which is why I came here to check and see what I should do to prevent my gearbox from chewing up pistons like there's no tomorrow.

I got maybe 4 3-second bursts out of my gun in the second round before I snapped the piston. Also taking into consideration that I had only used up 500 rounds out of my C-Mag at that point, and I'd say I definitely have a reliability issue with this weapon.

Unfortunately going beyond 9.6V for me is more risky than the internal upgrades I've been doing, because I've seen people's AEGs burn up from too high of voltage. Considering the sheer ROF I am after (shooting for 45-60rps), electrically it would be unwise to run a 13.2V (possibly higher, this is based on a quick-n-dirty calculation..) battery pack. What is one to do to get a pocket-sized support weapon?

[IcePlatinumSky]

No I was saying that a 9.6 or higher is to much. I have high speed gears and motor in my G36. I use a 8.4 1800 large and get a wicked ROF. 9.6 is just going to blow out the piston to fast.

[JoJockAmo]

what brand pistons

[warlock]

The first one it snapped was the stock CA one.

The second was an unknown, I borrowed a spare piston from someone so I could make it to Red Sleigh without having to worry about the piston getting here in time.

The one I have now ordered is the Matrix piston with full titanium teeth.

[JoJockAmo]

Yah CAs are :cry:
I love me some guarder pistons

http://www.airsoftmechanics.com/reviews ... =5&page=12

review on pistons

[azsarge]

Using the same gun, CA M15A4, if I pick up a M120, bearing piston head, cylinder head, and a bearing spring guide, will I be able to leave everything else stock? - Joseph

Check and see whats in that box first.

The newer CAs supposedly come with what ammounts to a silent head set and bearing spring guide already installed from CA.

CA bushings are GTG.  

Every AEG needs a silent head set and bearing spring guide, metal bushings, and a good nozzle.  I only swap pistons when they break.  I've never had to on any of my AEGs.