Vfc m4 sopmod

[Korunos]

I've been having this problem lately where for the 1st 5-10 shots out of all my mags shoot about 190-200 fps on 25's. After that, the gun returns to normal fps ( about 370 fps ) I'm using the stock hop up unit, recently replaced the hop up rubber with a Madbull one, oiled it up and slid it in place. This is with the hop up fully off as well. The mags I am using are the Magpul Pmag ( 120 rounds ), this problem has only started within the last 2 weeks.

Any ideas are appreciated.

Also, anyone have a suggestion as to what would be a good hop up upgrade on a VFC M4? I've tried a Modify once before and suffered a massive FPS loss. Something to do with the nozzle not meeting up properly with the unit. Nozzle too long, or too short...I can't remember.

Thanks everyone.

[MaciekA]

with respect to your upgrade idea, you could try the modify one again and try two things:

1) Push it harder against your mechbox. If it helps, put teflon tape or o-rings around the spot where your barrel meets the hopup unit. Anything squishy that can push your hopup back a little bit against the mechbox.

2) Wrap the bucking with dental floss (search "maekiii dental floss mod" on youtube) OR wrap the barrel with some teflon tape and then put the bucking around that to ensure the seal.

Both of those things may help bring your Modify hopup unit back in business. It is really quite a nice hopup, so it's worth trying to get working.

[Rabbit]

Funny you mention VFC & hop up units.

I'm currently working on a VFC 416 having the same issue with the Modify hopup unit - lost 40fps with it - automatically i figured it was the nozzle as well not mating.

Originally Posted by MaciekA

o-rings around the spot where your barrel meets the hopup unit

Do you mean the outer barrel? So say - just infront of the hop up unit where the inner barrel is inserted? think I have an o-ring i could try.

[MaciekA]

Originally Posted by Remylebeau

Funny you mention VFC & hop up units.

I'm currently working on a VFC 416 having the same issue with the Modify hopup unit - lost 40fps with it - automatically i figured it was the nozzle as well not mating.



Do you mean the outer barrel? So say - just infront of the hop up unit where the inner barrel is inserted? think I have an o-ring i could try.

You know the spot where there's often a little brass ring that slides onto your inner barrel and then fits inside of the hopup unit? basically slide an o-ring onto that area but still have it on the barrel.. just something squishy to tense it against the mechbox. It's not always enough, so experimentation is required.

When getting the Modify Accurate hopup to achieve good fitment in a G&G body, I noticed that this mod would raise the fps of that particular setup from 395 to about 425, and the feeding was stable also. Your mileage may vary.

I find it amusing that Modify's parts have oddball fitment with VFC and G&G, considering all these folks live on the same small island and probably occasionally have beers with each other.

[Korunos]

Will give the teflon tape suggestion a try, thanks much.