phantom won't maintain velocity

[dracowing14]

I purchased a cci phantom from a local store a little while ago, after buying the gun i went across the street to the field to try it out, unfortunately the gun wouldn't chrono below 320 FPS some have suggested cutting the spring but i was too scared i'd mess something up. so today i thought i'd try to work the velocity again this time with my own chrono I'm using a stock phantom with the vertical air kit, It has the old hard steel lines not the macros. I'm using the A-balls right now just so i don't make amess and i've screwed my 68ci 4500 tank directly into the bottom. The shoots aren't consistent my first shot got me about 269, my second got me 340, my third got me 180. and so on for about 10 shots i tried dry firing a few times and then retried with the chrono, with the same results. any idea's the gun itself hasn't been used in probably 9 months. and it's only had 4 real paintballs put through it.

[thkyle]

Have you striped the gun and looked at the condition and location of the TPC?

[dracowing14]

I'm new to phantoms so what part is the TPC. also I've noticed that when i strip the gun and re-assemble it and give it a good shake i don't hear anything, but after the first cock i can hear the hammer assembly moving around inside. I havnet put any upgrades on this gun yet. but i was thinking of replacing the springs as well as getting some detent rings

[thkyle]

I had a feeling that you were new to the Phantom. It's a fine gun and welcome to PHOG.

The TPC screws into the center of the bolt and is how you adjust the tention on the main spring and thus control the velocity. I suggest that you get familiar with all the parts of your new gun. There is a a lot of info on this site. MCB and at phantomonline.com.

This will help you a lot if you can learn how the gun works and what each part does. We would simply be guessing at what is causing your problem, but it doesn't sound like changing the springs is going to help. You should first check the manual and make sure that the TPC is adjusted properly and also that there isn't a big difference in the size and fit of the paintballs.

The TPC should never be more than 5-6 turns into the bolt or it can come out and cause a lot of problems. Try setting it to 3 turns and then adjust from there. If that doesn't solve the problem then we can try some other ideas.

[dracowing14]

I have removed the TPC once or twice before during cleaning but the threads still look fine on it I'm starting to wonder about the noise I'm hearing when i shake the gun. I know it is the hammer assembly sliding inside and i don't think it should be but what do i know. on that note i have never really looked at the nylon screw so it might not be holding the tpc properly. on another note i did read a post from somewhere that someone had a similar problem and it turned out to be a broken power tube. i don't see anything wrong on mine so I'm going to rule that out for now.