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VERY high velocity on custom 98 |
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DeeV0n 
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Joined: 17 August 2008 Location: Canada Status: Offline Points: 2 |
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 Topic: VERY high velocity on custom 98Posted: 17 August 2008 at 1:08pm |
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Hello, I have a Tippman custom 98 that is shooting at an extremely high velocity. I'm talkin between 365-391 FPS. My 98c has a cyclone feeder installed and I regularly use a flatline barrel with collapsable stock. I also have a 14" .68 caliber lapco barrel. I use Co2 with my gun, not HPA I went to a tournament last weekend where my gun chronoed at 375 fps with the velocity adjustment screw flush with the outer casing. Seeing as this was much too high I adjusted the screw inward as far as it could go and got it to go only to about 360 fps. I had to use another gun. I came home and took my gun all apart, cleaned it inside and out and tried again, only to have the same problem. I tried it with the lapco barrel installed and it shot at 390 FPS!! I've been reading through these maintenance forums and only suggestion that I could see that remotely fit my situation was that perhaps the hammer spring was very strong, but shooting at 370 FPS with a flatline installed seems to be a bit much for just a strong spring. Also, it used to shoot within acceptable levels before this. The only other thing I could see is that perhaps when I installed the new powertube for the cyclone feeder I did something wrong? I don't know.. any suggestion would be greatly appareciated, I have nice gun... I just wouldn't want to play with it and hurt someone cause it's up WAY too high. |
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If it breaks in the barrel once -- bad luck. If it breaks in the barrel twice -- Why didn't you clean your barrel after the first break?
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Beil
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Joined: 12 July 2008 Status: Offline Points: 113 |
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Posted: 17 August 2008 at 2:37pm |
what was the temperature outside? on hot days, your gun will often times shoot much higher than it normally would. I only mention this because you said your gun has shot within acceptable limits before. the main spring's spring rate (the spring that's inserted into the rear bolt) is what dictates how hard the bolt hits the valve, how much air is released, and therefore how high the velocity is. i'd suggest one of two things: cutting one coil off the spring at a time, chrono-ing after each cut, or buying a spring kit, and switching out your spring for a lighter one. modifying/switching out the spring will do two things: first off, it'll lower your velocity to sufficient levels. secondly, it'll allow you to back the velocity screw so that it's flush with the inside of the powertube, therefore getting optimum efficiency out of your marker. |
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I do it fast, slow, hard, and easy. I sometimes even do it in the woods. Yeah, I'm a runner.
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DeeV0n
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Joined: 17 August 2008 Location: Canada Status: Offline Points: 2 |
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Posted: 17 August 2008 at 6:05pm |
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It wasn't very hot, warm enough so that you could wear a sweater or a t-shirt. It seemed to be about optimal conditions for play that day actually. I will most likely try modding the spring then, if that doesn't work I can always buy a new spring kit later. Thanks a lot for the advice. Edited by DeeV0n - 17 August 2008 at 6:06pm |
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If it breaks in the barrel once -- bad luck. If it breaks in the barrel twice -- Why didn't you clean your barrel after the first break?
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oldpbnoob
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Not old, Not noob. May be Dave's grandma Joined: 04 February 2008 Location: Yankee Stadium Status: Offline Points: 5676 |
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Posted: 18 August 2008 at 1:29pm |
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Out of curiosity, did this issue start before or after you put the aftermarkert powertube in? If it only started after, take the powertube out and try putting the stock one back in.
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"When I grow up I want to marry a rich man and live in a condor next to the beach" -- My 7yr old daughter.
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K Hop
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Strike 1 F-bomb in link 9/29 Joined: 23 May 2008 Location: United States Status: Offline Points: 554 |
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Posted: 18 August 2008 at 4:16pm |
its for the cyclone. but thats what i think the problem is |
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oldpbnoob
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Not old, Not noob. May be Dave's grandma Joined: 04 February 2008 Location: Yankee Stadium Status: Offline Points: 5676 |
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Posted: 18 August 2008 at 5:12pm |
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Ok, I am guessing that he put the replacement powertube in that comes with the Cyclone feeder. I skimmed, saw the word powertube and thought he might have put in an aftermarket one. If you used the powertube from the cyclone kit, you shouldn't have issues as it is still GTA. How about the stock? Compare the depths of the holes that the spring fits into to insure they are the same depth. If the hole is more shallow, it can increase the pressure on the spring and cause higher FPS. What type of stock is it? Edited by oldpbnoob - 18 August 2008 at 5:14pm |
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"When I grow up I want to marry a rich man and live in a condor next to the beach" -- My 7yr old daughter.
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K Hop
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Strike 1 F-bomb in link 9/29 Joined: 23 May 2008 Location: United States Status: Offline Points: 554 |
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Posted: 18 August 2008 at 6:23pm |
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try removing one thing at a time, such as the cyclone and the new powertube and try it with the old powertube (if you didn't throw it away). if that doesnt help take of the stock and put the old endcap back on if you still have it. it should help find what the problem is and what is causing it.
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DeeV0n wrote: