Tighter Barrel = Drop in FPS!

[Ben200987]

I've recently changed the barrel in my G&G G26 from stock to a Madbull 6.01 229mm barrel and my FPS has done the opposite to what I had hoped. It's dropped by 10fps. Can anyone shed some light on this for me please?

[Mike636]

It may just be the airseal around your hop up rubber isnt as tight as it was before, try a bit of teflon plumbers tape to try improve it and did you lube up your hop up rubber before you put it on your new barrel?

[Suzuki Yamamoto]

Your 6.01 barrel might actually be too tight, a 6.03 might be a better option.

[Ben200987]

I lubricated the outside of the bucking but not the inside? I do have Teflon tape but I was unsure where to put it?

[Mike636]

If you put teflon tape around where the barrel leaves the hop up unit that should improve your airseal. Is the new barrel a different length to your old one?

[Ben200987]

Ok thanks Yes it's about 20mm shorter than the stock barrel.

[Mike636]

That may be a factor too, but TBH 10 FPS isn't too much of a drama but the teflon tape mod might help bump it up.

[Ben200987]

Ok cheers for the info. I suppose I was just expecting to see an increase in the fps that's why I'm disappointed but I will try some tape this evening.

[snowy70838]

If you're using a tight bore barrel your BB choice is important.

 

Poor quality BBs won't do you any favours.

[Ben200987]

That's interesting, would you be able to recommend any?

[Mike636]

I use ASG Blaster .25g BBs never had an issue with them, heavier ammo will also move at a slower FPS. most site limits are based on a .2g BB

[Ian_Gere]

Did you clean the new barrel?

[ScoobySnacks]

Could well be that the BB's you are using are actually experiencing more friction from the barrel walls. Also, that reduction in length could have a significant effect. TBH most airsoft guns I've chrono'd have had a bigger variance than 10fps anyway!

[Tariq]

Not really sure on the fluid dynamics of an AEG piston/barrel but;

 

For gas guns the expanding gas needs room to expand into. So getting a tighter barrel that is the same length actually gives less room for the gas to expand. Thus a lower fps.

[Ian_Gere]

In a longer barrelled AEG .03mm tighter can = +30FPS

 

Also my A&K springer SVD went from somewhere around 440 with 0.2's to 438-441 (ie way too hot) with 0.3's with just a same length 6.01mm barrel upgrade and change of piston O-ring - I've had to put an M135 spring in it to get under 500FPS w/ 0.2's

[Ben200987]

Did you clean the new barrel?

No I didn't clean the new barrel. I've ordered some ASG blaster bbs because apparently they are more consistent in size so should be better for tight barrel.

[jcheeseright]

clean it, it's probably still full of gunk from the factory which is why you're seeing a performance drop!