At a public game recently I took my G&P Stubby Killer to have a smaller, compact weapon. When I ordered it from WGC I asked that it be 1 J compliant, and when I did the chrono at home it came in at 98 m/s so I thought "perfect, just legal."
At the game yesterday I stepped up to the chrono and it came in at 99 and 101 so they disqualified it and asked me to be careful with it. They were nice enough about it, but I felt bad about taking an over powered weapon. I was sure it was going to be barely legal...after lunch I realized the hop was off so turned it completely up, explained to the staff that I had adjusted the hop and would like to re-chrono. They were OK with that, and it came in a 105 m/s. Oops, I must have turned the hop off by mistake. 1 last adjustment and they tested it again...95 m/s. They told me as long as I kept the hop the way it was they would allow me to use it. I thanked them, as I was tired off hauling around my bigger weapon, and off I went.
I then realized that I had done the chrono with .25 bbs by mistake. I loaded .2s, explained the situation and that I was concerned about other players safety and did a 3rd round at the chrono. It came in again at 101, so it was a no go. The organizer thanked me for be so safety conscious and that he really appreciated my honesty.
All this to say that my hop is opposite of what I expect. I just tested at home and when the hop is completely off I get 99 m/s and with it completely on I get 110 m/s!
This is with fully charged 9.6v 2200mAh batteries.
So I need to get it fixed, and I am wondering what to do. Do I replace the hop up unit? Barrel? Or is a spring swap the only thing that is really going to bring it down? Weaker battery? All the above? What is the cheapest, EASIEST mod to bring DOWN meters per second.
Any advice is appreciated.
As a side note, I think that this is also a good example of why it is important to chrono our weapons at all games, even our private ones. I certainly didn't knowingly use the weapon "hot" and made sure I didn't when I found out it was. Having a reference point for everyone on game day is important, levels the playing field, and makes sure everyone is safe. My 2 cents.
I told you dude, didn't I ?! I had the same issue with mine, had to cut the spring a little, and now it's again "just legal" (though I only had my home chrono to check it).
You need to take the spring out, and cut maybe half a revolution, or maybe a full one, flatten again a little the end, then file the sharp edge so it doesn't damage the box. Best is to cut it at the loose part of the spring, so the part that is not in the piston, but toward the box outer side.
I made mine go from 1.15 to 0.98 like that. WGC doesn't do shit beside giving you some fancy papers.
You were right my friend.
I have a .9 Angle that didn"t work with my SOPMOD. I wonder if I could just put that in if I have to open it up anyway...
No, it won't work. I bought 2 different springs, a Systema 1J and a King Arms 1J, I tried the Systema and it didn't give me anything close to 0.9, more like 0.7, was so mad.
Reason is, the BB is probably propelled out of the barrel too fast and the piston doesn't get the chance of giving a full blow. That or the mechbox/hopup seal is bad and too much gets out.
Either way, the current spring you have is probably a 2J or something in the likes. Replacing it by a 1J will get you a very shitty output. My barrel is longer than your gun's, and I was getting 0.7 with a 1J spring, imagine how much you gonna get...
Didn't someone insist that we should never ever ever cut springs?
I think it was...Fareast maybe?
Also, "barely legal." Hehe. Ok, I'm done now.
Hu, don't know, got my advice from Q, and it worked fine, and still does.
Of course you need to re-flatten the cut part, and not keep a sharp edge sticking out, that would be definitely wrong. But else you should be fine.
What do you mean by re-flatten?
When you take the spring out, you'll see that both side are "flat", there isn't a sharp edge sticking out, so both sides of the spring make full contact with the piston and mechbox on each side.
When you'll cut the spring, you'll have to cut part of the flatten surface, and will need to re-bend the end, to "re-flatten" it, after filing it properly of course.
Remember the dense part of the spring is toward the piston, the loose one toward the end of the gun (mechbox). My advice is cutting the loose part as it's easier to manipulate and re-bend after.
Cheers !
Thanks for that Ycare. I will give it a go when I have the courage to open up the box
To shave some FPS off the spring sand the outside of the spring with fine grit sandpaper, this will remove some of the surface area and weaken the spring slightly.
Also you can take a blowtorch/Pipe torch to part of the spring this will also remove tension. Enough to remove about 5-8 fps.
Some of you will remember Carl from AI doing this to my M4 last time I played at Union with a cigerette lighter.
Some other things you can do to lower output without touching the spring:
1. Remove bearings from piston head and retain one washer (if applicable)
2. Use a stock Tokyo Marui spring guide (again, if applicable)
3. Short stroke - either by replacing the gearset with a Phoenix Super High Cycle Set (
this one) or cutting the first 4 teeth from the sector gear that's inside the gun. This will decrease muzzle velocity by not compressing the spring fully. This will also (a) reduce instances of a partially-compressed spring after a semi-auto shot and (b) reduce chances of the sector gear catching the piston in mid-cycle in full-auto. Not to mention an increased rate-of-fire when using at least 9.6V battery.
I put my Angel .9 Joule Choppa Spring in to test it before cutting down the spring that was in G&P. As it turns out I get from 82 m/s with the hop off to about 88 m/s with the hop on which works well for me as I can also use it indoors.
I have 3 quick questions though if someone could help me out...
1. Should the denser coil of the spring be at the spring guide end or the piston head end?
2. The bearings don't sit very well, to the point that some of them fall out when I open the case. Is that an issue? The G&P is a "Reinforced 7mm Bearing Gearbox" so I could probably pick up replacements. When the box is closed I can push the bearings in from the outside as they aren't flush otherwise. Should they sit flush with the inside or outside of the gear box?
3. Should the fin or hook on the tappet plate sit above or flush with the tappet plate guide on the sector gear? When I reassemble should the guide be touching the tappet plate or a bit in front of it? Mechbox.com suggests 1:00 position, but this is with a TM gear set that has a much smaller tappet plate guide. Please see the photo for an idea of what I am talking about.
Happy to have pulled a version 2 box apart and that a spare spring did the trick!
The trigger on the G&P is horrible though and just won't stay in place when the box is open...I know, you warned me Ycare
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(30-09-2009 09:25 PM)dstole Wrote: [ -> ]1. Should the denser coil of the spring be at the spring guide end or the piston head end?
Coils with shorter pitch - I guess this is what you refer to as dense - goes to the spring guide side
(30-09-2009 09:25 PM)dstole Wrote: [ -> ]2. The bearings don't sit very well, to the point that some of them fall out when I open the case. Is that an issue? The G&P is a "Reinforced 7mm Bearing Gearbox" so I could probably pick up replacements. When the box is closed I can push the bearings in from the outside as they aren't flush otherwise. Should they sit flush with the inside or outside of the gear box?
Except when they're very loose or the bearings are visibly smaller thant he holes, this is no issue. And, ideally you shouldn't be able to push the bearings in an assembled gearbox. Being able to do so means the gears aren't shimmed correctly. Incorrect shimming can lead to damage to gearbox internals.
(30-09-2009 09:25 PM)dstole Wrote: [ -> ]3. Should the fin or hook on the tappet plate sit above or flush with the tappet plate guide on the sector gear? When I reassemble should the guide be touching the tappet plate or a bit in front of it? Mechbox.com suggests 1:00 position, but this is with a TM gear set that has a much smaller tappet plate guide. Please see the photo for an idea of what I am talking about.
The sector gear should be in a position that it isn't engaging the cutoff lever and not meshing with the piston rack teeth when you close the gearbox. This position will not necessarily cause the tappet plate and the nub on the sector gear (it could be technically called a cam) to touch.
With the power you get with the G&P spring, just short stroking will give you around 88-92 m/s. What did you do exactly?
Thank you for your tips and terminology Hazard,
All I did was open the gearbox and remove the G&P spring and replace it with the .9J Angel Choppa spring of the same length.
I put everything back the way I found it, shimming, bearings, etc and tested it over 10 rounds. I averaged between 82 and 88 m/s.
I have now opened the gearbox again and will reassemble after I decide if I need to replace any other parts.
Oh, and the image in the last post wasn't mine, it was one I found online that looked pretty much like my G&P but I hadn't re-opened it yet.
Also, another thing worth mentioning is that the stubby killer has a very short inner barrel (166 mm) and has a non-ported cylinder so that might account for the lower power as well.
(30-09-2009 10:40 PM)dstole Wrote: [ -> ]Also, another thing worth mentioning is that the stubby killer has a very short inner barrel (166 mm) and has a non-ported cylinder so that might account for the lower power as well.
And despite that it shot over a hundred before?
That is a monster spring. Angel choppa springs are strong and can reach over 100 too if installed in a system with the correct ratio.