Polarstar Feeding Issues

[Viper]

I posted this up on P* Talk and got minimal responses so far. Maybe my MIA community can help with this.

I'm going to try and make this as descriptive as I can because I've tried everything I can to find the problem with this. Even going as far to buy a whole new gun and mags to drop the FE into...

The setup:
Madbull metal body
R-Hoped Madbull 300mm 6.03 barrel (R-hop now removed, thought that might be the issue)
V2 Gen 3 FE (gold poppet/silver nozzle)
90/4500 Ninja Grey Tank SLP
ARX20 regulator (95psi test pressure)
Prowin hopup chamber (tried flat nub and shs concave nub)
Madbull Ultimate hopup chamber
PTS E-mags
Bioshot BB's (.30, .28, .25)
Goldenball BB's (.30)

The problem:
The gun will not fire every shot.

Explanation:
When I leave the settings on the FCU stock, the gun seems to cycle fine and air is sent down the barrel. When a mag is inserted it sounds like and appears to take 2-3 cycles to fire a bb. Almost as if the gun is loading the bb into the hopup chamber and then firing it on a subsequent pull of the trigger. I've tried Promy, King Arms, Guarder and Madbull buckings. All seem to do the same thing. (Granted the Promy ones take 5-6 shots to fire the bb's) This is with the .30 bioshot bb's.

When I put a mag of bioshot .28's in the problem seems to go away completely. And comes back when I use .25's. I can't imagine that this is due to the weight of the bb's. I've played with FCU settings with each bb and I'm thinking of just getting some G&G bios or something else to try. Also happens when I use the new Goldenball .30's (thought maybe it was the BB brand)

Has anyone else had this problem where it fires every second to third shot and they figured out what the problem was? Alignment maybe?

Any help is appreciated.

[TheEnd]

According to this thread a lot of people had feeding problems with them too. Lubing the mags seemed to help, but I think that is a bad idea in general and would probably be worse with biodegradable bb's.

When I have this problem (in my AEG's) it is usually due to the bb's having a rough surface which binds up in the mag, or the mag to hop up fitment is bad. Since you have a P* your nozzle solenoid could be an issue although it working with .28's sort of rules that out.

A few things to clarify:

- Does the problem still happen if you push up on the mag?
- I noticed you listed two hop up chambers, did the problem happen with both?
- Does your Madbull still have that little rubber o ring on it?
- Do your mags feed in other rifles?
- Have you tried other mags in your rifle?

[Viper]

End, Here are the answers to your inquiries:

- Yes, the problem does not go away when I push up on the mags. The mags sit pretty tight in the well and aren't really capable of moving around all that much.

- When I originally installed the FE I put a brand new Prowin in and had this problem. Then I swapped it out with the Madbull Ultimate that was in my AEG at the time to see if that alleviated the problem. It did not.

- No, I got rid of that O'Ring that holds the bb's in the well even after the mag is released.

- Yes, I handed them to my buddy and they feed fine in his G&G and Classic Army.

- I originally had an old set of MAG brand mags and they fed flawlessly in my AEG for 6-7 years. Then I thought they may just be feeding too slow for the P* when I got the FE and purchased a new set of E-Mags. The problem continued.


I'm going to try and install my old AEG gearbox in the spare lower that I have and see if the uppers and mags feed with that tomorrow night. Maybe that might shed a little more light on why this damn thing doesn't feed like the almighty it should be.

[Gimpalong]

Viper,

I had a similar issue with the rifle cycling, but only actually firing every other shot. What fixed the issue for me was making sure that my on/off valve on my rig was turned all the way on.

Probably not the same issue that you were having, but I thought I'd just put this up.

[Viper]

What air rig are you using Gimp?

[Gimpalong]

Hey Viper,

I use one of the older Redline Devgru rigs with the AKA SMC-III Regulator.

[Cam]

If at all possible, remove that hop-up and barrel assembly, and test it in a working gun. Also, how quickly does your nozzle return? I received mine lacking oil, so the nozzle would return very slowly. If this is the case with yours, lube the front nozzle generously, and your problem should be solved.

EDIT: Noticed the part about taking several cycles to fire 1 round. ^^This should be the issue. Give it a good lubing, and you should be all set. If that doesn't work, then I would try removing the barrel, etc..

[Viper]

I just put together another AEG gearbox and put it in the spare lower I have from using both uppers for the P*. Tonight I will hopefully be able to test and see if I can just swap the AEG lower with the P* one.

Cam,
I swapped the standard blue nozzle with a silver and thought I lubed it good enough. I will take it out and make sure it is still lubed adequately.

[Cam]

The O-Ring on the silver nozzle might be old and dried out. Make sure it moves super smoothly to ensure that it functions correctly. I had the same issue with mine.

[Viper]

I will check it tonight and make sure it is lubed enough. Thanks Cam.

[Viper]

Update (double post):

Last night I put together that other gearbox and dropped it into the spare lower receiver I had and tried both the M933 upper and the MK116 Silenced upper. Both uppers shot great without having to do a thing to the uppers or hop ups. Maybe because a regular AEG box is more forgiving to alignment issues than the P*? I'm not sure.

I then removed all the pins in the P* lower body except the trigger pin to allow the FE to rotate in the lower. (Grip and Stock were also removed) The Madbull body that I have also has a threaded insert in the stock tube that acts as a stop on the back of the gearbox/FE to alleviate the stock tube pulling and messing up alignment. This was also back completely off allowing the FE to rotate back completely.

I then just shoved the shorter M933 upper on and tried to fire. It shot, surprisingly. It cleared an entire E-Mag with only 3-4 shots not coming out. Tonight I am going to try the O'Ring mod on the front of the hop-up to get it to push the FE back a little more in the lower housing. (I was using the old reliable King Arms metal hopup for this test because I knew it worked flawlessly in my other AEG's)

It appears that alignment is hella important in these damn polarstars. I'll report back on what works and what makes it impossible to get right when I do some more testing tonight or tomorrow.

Any more suggestions are welcome. And thanks to those who threw out ideas already.

[slippy]

Since no one at all has mentioned it try upping your nozzle dwell. It will allow the nozzle more time to feed the round, the difference is literally only milliseconds. Otherwise check your alignment. Www.airsoftjunkiez.com sells shim kits. A few thousandths of an inch goes a long ways and it only costs a little.

[Viper]

Slippy just finished some more testing last night. I tried upwards of 40 on the Dn and still had no effect on the feeding issue. Here is what I tried last night:

Being a Madbull body, it has a screw in the stock attachment tube that is supposed to hold the gearbox in place when you screw in a stock tube. I removed the rear body pin and the hand grip. Thus now I can rotate the FE in the lower about the trigger pin. So, now this stock screw can basically change the angle at which the FE engages the Hop Up.
So I tried about every engagement angle I possibly could and still had no luck getting it to feed. I then took the whole FE out of the lower and replaced it with a freshly built AEG gearbox. Put everything together and voila, the gun fires just fine... Take the AEG out drop the FE back in and test again, sh*t... There has got to be something I'm missing in this whole thing.

Anyone have any other ideas as to what my problem might be?

[slippy]

Viper,
My only advice at this point is to call the number listed at the link I posted. Those guys live and breath p*. They are incredibly helpful and willing to share knowledge, customer or not.

The shims I mentioned are a dual pronged fix.

1. If your nozzle is not seating far enough into the hop-up it will cause feeding issues.
2. The screw in your buffer tube, if improperly shimmed, can lead to an improper angle for your nozzle sitting in the hop-up.

Something to keep in mind is the P* was designed using VFC specs. Using a brand other than that can negate the engine being truly "drop in". I know the current gen works very well in KWA and VFC bodies. Gimpalong's seems to perform very well in a G&P.

Just call the number and ask to talk to a tech. Remember to be as specific as possible. With these things the smallest detail can make the biggest difference.

Hope this helps.

[Viper]

Yeah, I've been talking to Rodd at Polarstar directly. I'm probably going to be sending the whole gun into him to see what the issue actually is. I've invested a lot of money into the Madbull parts and if those truly are the culprits I'm going to be wicked pissed. Rodd did also say that VFC bodies are the base for the PR-15 full guns.

I know I have everything aligned. The one nice thing about the madbull body is that the buffer tube has that adjustable screw to change the angle of engagement with the Hop. Things look great down the barrel. But I just cannot get it to shoot every trigger pull.

I'll keep this updated with what P* finds when they get the gun.

Thanks for the help Slippy