Gradual FPS Decrease

[Vesper]

My AEG has been acting up lately.

When I first installed new parts into my gearbox, it was shooting 385 to 390 FPS with .25 gram BBs and an M125 spring. After 2 months or so, when I chronoed it, it was reading about 340 to 350 FPS with .25 gram BBs.

I opened up the gearbox yesterday, and I couldn't find any particular problem. The bucking wasn't ripped, and the compression is still top notch. Suspecting that I may have a faulty spring, I switched it with my M120 spring, and I'm still only getting about a 100ft range and the gun is shooting only through one side of a Coke can.

What the heck?

[VoidSuicide]

Keep in mind that these are only my humble inexperienced thoughts, but could it be that the gear box isn't fully pulling the springs for some reason? or could there be some kind of build up in the barrel?

[Vesper]

Keep in mind that these are only my humble inexperienced thoughts, but could it be that the gear box isn't fully pulling the springs for some reason? or could there be some kind of build up in the barrel?

I clean my barrel rather frequently, and the gears and the piston don't seem to be missing any teeth, so I don't think that's the case.

[Dominum]

Use a real chrono and decompress your spring after you use the AEG.

[adjunog]

The spring may be binding up. Is there any bearing parts for your spring guide or piston head? Any one of these parts can help from binding spring problems.

[Vesper]

The problem is solved a long time ago. Thanks for your help though.

[Dominum]

...and again I find myself having to debunk a factually incorrect assertion. Let me say this, I have nothing whatsoever against you Adjunog, but it would be grossly negligent of me not to point stuff like this out. Do not take this personally, I am merely stating the facts.

He was complaining about a gradual loss of FPS, which by definition could not be a spring binding up. There are only two possible outcomes of a spring binding up: either the spring breaks in two (or more) parts and is ruined; or the gearbox will not finish it's cycle and will remain locked up due to the spring being enable to fully compress, and thus the piston being unable to return forward as it is only halfway cycled back. In either case, the gearbox cannot complete a cycle with nothing more than a noticeable lack of power if this is the case, hence this diagnosis is impossible given the symptoms.

[Hotspur93]

I vote we call you Dr.Dom from now on and whenever you work on a gun you have to wear one of those white headbands that have the metal disc on them and also a stethoscope xD