M4 fps

[ROAR]

so ive upgraded my mechbox put a modify 100 spring and a modify 110 spring and i still get about the same fps between the two, im wondering if theres something else wrong, like the inner barrel or something. Or should i try another diff spring, I would like it to shoot around 350. Any suggestions?

In the Mechbox (I Beleive its a G&P Mechbox) is....

Deep Fire Titanium Piston (Full Teeth) - New Version
Modify Aluminum Bearing Piston Head
Modify SMOOTH Modular Gearset 7mm V2/V3 - High Speed
Marui EG1000 Long Motor

the rest is pretty much original

Help!

[kalnaren]

Originally Posted by ROAR

so ive upgraded my mechbox put a modify 100 spring and a modify 110 spring and i still get about the same fps between the two, im wondering if theres something else wrong, like the inner barrel or something. Or should i try another diff spring, I would like it to shoot around 350. Any suggestions?

In the Mechbox (I Beleive its a G&P Mechbox) is....

Deep Fire Titanium Piston (Full Teeth) - New Version
Modify Aluminum Bearing Piston Head
Modify SMOOTH Modular Gearset 7mm V2/V3 - High Speed
Marui EG1000 Long Motor

the rest is pretty much original

Help!

Anyone feel free to correct me on this.. Aren't metal pistons a bad idea? They'll be hitting the metal gears.

Anyways, check your seals around the cylinder head, nozzel, and hop-up.

[Crunchmeister]

What velocity is your gun shooting at now? Are you measuring this with an actual chronograph?

[CDN_Stalker]

Modify 90 spring and a bearing spring guide should sit you around 330-340fps based upon my experience. And the same set up with a Modify 100 spring should be around 360-370fps.

And metal pistons are a bad idea largely for V2 mechboxes and their inherant weakness in the same area. Metal gears on metal teeth isn't a big deal. He SHOULD expect the side rails that hold the teeth in place are likely to crack after a short while, I found that out with one gun I was just testing! Hadn't even been gamed yet!!! Get a Modify piston as well, even the basic one is excellent. And metal pistonhead.............. meh, should be ok, the G&P reinforced mechboxes are very tough.

[ROAR]

The teeth are the only thing thats metal on the piston and yes im using a madbull v.2 chrono. Im only doing abot 300 to 310 right now with the 110 spring installed.

ill check my seals, if i put the piston in the cylinder and put my finger so no air gets out of the end should the piston fall fast slow or not at all?

[CDN_Stalker]

Should either be not at all (fully sealed) or very slowly. Chances are you have a ported (small holes on the face of the piston) pistonhead, use dishsoap and warm water to clean the cylinder and O-ring, then give it a wipe of silicon oil and try again. The O-ring is supposed to inflate to seal, and if it doesn't inflate there won'tbe a seal. If you find the compression test shows no compression, try pushing the piston in hard and it might seal due to the O-ring inflating fully. Try it before and after washing. I've had issues with ported piston heads in the past, sometimes they can be tricky to make work right.

If you have a good seal, then likely something is worng with your hop up/rubber and the air leak is coming from there.

[TokyoSeven]

Other things to double check! Even though you may know them Im only putting it out there just in case you dont.

Make sure you installed the cylinder back in with the port (if applicable) towards the back. I wasnt paying attention once and installed the cylinder with the port forward.

Make sure the Oring around your piston head is lubricated, if its not lubricated then you will not be getting a full seal, and that could explain the air loss.

Make sure that the tigher coils on the spring are facing towards the back, that means put that end on your spring guide. A reversed spring can affect FPS.

Unfortunetly I cannot think of anything else aside from check for your basic leaks and missalignments. Best of luck.

[ROAR]

thanks guys ill check all that right now and let you know!

[CDN_Stalker]

Originally Posted by TokyoSeven

Other things to double check! Even though you may know them Im only putting it out there just in case you dont.

Make sure you installed the cylinder back in with the port (if applicable) towards the back. I wasnt paying attention once and installed the cylinder with the port forward.

Make sure the Oring around your piston head is lubricated, if its not lubricated then you will not be getting a full seal, and that could explain the air loss.

Make sure that the tigher coils on the spring are facing towards the back, that means put that end on your spring guide. A reversed spring can affect FPS.

Unfortunetly I cannot think of anything else aside from check for your basic leaks and missalignments. Best of luck.

Reversed spring will knock off up to 30fps, cheap way to reduce the fps if a bit too hot without having to buy another spring. He should be getting 370-410fps out of the springs he has, so it's likely an airleak or it's a chrony issue.

[ROAR]

well did all you guys said to do and still 300 maybe my chrono is screwed how do i test it/adjust it?

Ill do some more testing

[CDN_Stalker]

Originally Posted by ROAR

well did all you guys said to do and still 300 maybe my chrono is screwed how do i test it/adjust it?

Ill do some more testing

Have any other guns that you can see if they read correctly? Can't adjust or really fix it, so the only way is to grab another gun to test it. I always do most of my testing of ammo weights and brands with my TM MK23 springer because it's super consistant.

You could also try the pop can test, tell us what (point blank, bottom, sides, top) is penetrated and what is only dented. Will be a very basic means to sort out if it's your chrony.

[ROAR]

well took barrel and hop up out and cleaned and put back in and now (ran out of .20 for testing) with .25's im getting about 315 fps.

[CDN_Stalker]

So you are shooting around 340fps or so.

[ROAR]

Ya thats what i thought thanks guys for all your help!!!!!!!