Mysterious FPS - *coke can test

[DYORD]

My TM AUG has an SP160 setup.. though the spring is a year old already...(merely 2 bags of bb's used). It can still penetrate the top edge of a coke can using .2 bb @ 3 inches away. Can make a hole @ the central top, but can't get through it. I've read the coke can test thread.. based on it, my chrono should read 480-510fps approx. @ .2 bb.

Anyhow, I've played two gamesites and it only chrono-ed 370-390 fps using .28 bb's. Never tried using .2's on it(never had a chance). I'm not sure how much drop it should be using from .2's to .28's... I'm just frustrated to realize that the max fps I could get is only 390fps.

Any conclusions?
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[TokyoSeven]

Well, the drop sounds about right.

[LUTNIT]

480fps w/0.20's ~ 430-440fps w/0.25's ~ 390-410fps w/0.28's

390 with 0.28's doesn't surprise me if you shoot 480fps with 0.20's

[Crunchmeister]

My question here is: why are you frustrated with your velocity? If you were over 400 fps, you wouldn't be allowed to play anywhere. To me, 390 with .28s is pretty damn good if you ask me.

[Uziguy]

Thats gonna hurt!

[Brakoo]

Originally Posted by Crunchmeister

My question here is: why are you frustrated with your velocity? If you were over 400 fps, you wouldn't be allowed to play anywhere. To me, 390 with .28s is pretty damn good if you ask me.

You do realise that 390 fps with .28g is way over most field limits ? The FPS is calculated with .20 for a reason otherwise everyone would simply go for heavier BBs.

[Amos]

Originally Posted by Crunchmeister

My question here is: why are you frustrated with your velocity? If you were over 400 fps, you wouldn't be allowed to play anywhere. To me, 390 with .28s is pretty damn good if you ask me.

He's in the Philippines. IIRC, There's no FPS limit.

[Murdoch]

His profile says he's in the Philippines. Those guys run way hotter guns than we do here.

[DYORD]

yeah... I'm from philippines.. and 390 fps using .28's here are waay too low for our standard (honestly)..

I'm also a bit curious with the velocity.. thought my spring(SP160) is already a year old, why it shoots only around 480fps? I was expecting atleast 550fps or better.

[dodger_me]

get airsealing parts. and a get a new cylinder head, tb, piston head/piston

[TokyoSeven]

Is it only your spring that is upgraded?
Other parts such has the inner barrel can affect your FPS as well.

[Crunchmeister]

Originally Posted by Brakoo

You do realise that 390 fps with .28g is way over most field limits ? The FPS is calculated with .20 for a reason otherwise everyone would simply go for heavier BBs.

In my state of noobness (having never participated in a game), I was unaware of this. Thanks for the info.

And yeah, I didn't realize he was from the Philippines.

[DYORD]

Ok here's my upgrade; (everything else is stock)

SP160 (spring - 1 year old)
Infinite torque-up gears (stock anti-reverse latch)
Alum. halftooth piston body (stock piston head)
Non bore-up metal nozzle (the one with 2 o-rings inside)
Metal hop-up assembly & prometheus hard type hop-up rubber.

everything else....

stock TM barrel
stock TM Cylinder & cylinder head


so what you think?!?

[TokyoSeven]

If you upgrade to a tigher inner barrel, it will provide your BB a little more push since it will provide a better airflow, Ive heard of up to a 20+ FPS with tigher barrels.

Upgrade your cylinder head as well, Im not quiet sure what to recommend though, perhaps someone can give some input onto that. I use a systema cylinder head that links to a deep fire nozel and everything seems to work ok for me, but Im not pushing high FPS in the first place.

[ILLusion]

swap your cylinder head. The stock TM one is crap for any high velocity applications.

You might want to also consider swapping to a ventilated piston head with bearings. It'll provide a better seal, especially at high velocities. It'll create a really nice and tight seal between the o-ring and cylinder wall.