Premature piston wear?
 

This is actually a couple of issues, more or less I'm wondering if this piston is still usable. This is all speculation and somewhat educated guesses(I could be way off)

I'm running a stock CA AK SLR-105 with a large 9.6v 2000mAh. My initial concern was the battery was too hot(the guy at the battery store made an 8cell instead of a 7). My fears were confirmed when my gun was double firing and generally loading erratically and causing the gun to jam, and on semi it would half cock the piston on the second shot.

Well, after the first 10 minutes, it jammed completely, and couldnt turn the gears over in the mechbox. I took it apart, and the first thing I noticed was the screw that held the piston head on had fallen off. The second, was a groove worn down the center of the piston, obviously from the sector gear.

http://i306.photobucket.com/albums/n...Picture463.jpg

Not the greatest quality but it gives you a general idea. While its apart, I'll upgrade the spring, nothing to extensive, just so it shoots around 360ish. Two other concerns

1) With the stiffer spring will running a 9.6 slow the gear box down enough to rid myself of this feeding/jamming issue? Or should I just bring the batteries in and take a cell off to make them an 8.4

2) Should I go with a full tooth piston? Can I use the one I have, or just buy its direct replacement? Assuming all common internal parts fit CA guns

Thanks in advance

your piston may have been made of poor material.

your piston head coming off was probably the cause though.

buy another full tooth piston. thread lock the piton head screw

Though the high ROF is likely what causes the piston head to fall off, I doubt the battery is to blame.

Replace the piston head and piston and loctite the screw so that it doesn't shake loose. (you can also use nail polish if you dont have loctite) I would use a Modify full tooth polycarbonate piston and Modify piston head or the ARS MASK piston head. Double check your AOE just to be sure.

That looks to be a CA Yellow piston (Hard to confirm because of the photo colours)

If it is.. throw it out. CA Yellow pistons are awful.

Replace it with a stock tokyo marui, Prometheus or System supercore :)

+1 on that, CA pistons just suck in general..

throw in a new (modify quantum/pick your poison) piston and it'll be singing.

just be sure to CLEAN ANY PLASTIC SHAVINGS out from the gearbox nooks and crannies, otherwise you could end up with stripped gears in future.

Your battery is not the issue. Feeding issues and such are other mechanical issues and not electrical.

Well, here's why I thought it might be the battery;

I bought the gun about 3 weeks ago, and have plinked around with it around the house with an 8.4v 1500mAh large battery with no issues. I then had a 9.6v 2000mAh large battery made for me, which had a little charge on it. So before I charged it up, I tested my friends TM mag through it. No problems. I put a full charge on it and the first game I play (I usually play on semi-auto) and I start jamming up. Without a mag in it on semi I notice the piston doesn't get a full cycle on the second shot.

Eventually after the first game(basically of me unjamming the gun constantly) it just seized up. When I got home later I took it apart and saw screw had fallen off and jammed it

And yes, it is a CA piston

FYI not a good idea to use prometheus piston without prometheus gears. The only instances I've ever heard of them stripping were when they were used at high ROF with non-prometheus gears.
+1 on the marui, modify and systema pistons

But CA pistons are crap, you can have one that lasts 3 years, and you can have one broken from factory. Don't trust them at all.

What brand are the cells on your new pack?

I believe they're sanyo

Does anyone recommend a full metal tooth piston?

If I don't need a full metal tooth piston at 1250rpm and 380fps, you definitely don't need one lol
I've never heard of a piston stripping in a gun I've upgraded yet, there's no reason to buy full metal tooth pistons.
Anyway if the problem isn't the piston, and the same bad thing happens, well then something other than your piston will break!

Alright, thanks for the tips, I'll stick with the full tooth polycarb piston. Guess I'll have an update when the parts get here and I get another game under my belt. Assuming all goes well in the reassembly, lol.