Vfc Scar Help - Feeding Issue

[paradoxum]

 

 

Parts list:

 

At my wits end here. can't figure out the issue. anyone, anyone at all?

 

thanks in advance,

para

[Alicks]

not overly sure tbh, just whistling into the breeze here, but potentially you have a "heavy" piston being pushed by a light spring

maybe with the 1:12 ratio your getting double feeds as the gears are doing more than 1 rotations before engaging the piston again

however the titan should be stopping that from happening

have you checked your titan setting are set up properly

also if you have not alot of power check that precocking isnt turned on

apart from that not sure mate 

[Stratton Oakmont]

Do you have a sector delay chip on your gear to ensure the tappet  plate timing is adequate?

12-1 gears may require one 

[Sitting Duck]

So you chucked all this together in one go ???

 

First thing - is it mag related

(do not refute this and then discover a shit midcap fails to feed from jammed bb's inside mag)

so try a few mags (known to work well in other m4 type guns)

 

OK - it is "likely" not mag related - given how much crap has changed

(but always best to confirm)

 

Hop/Bucking bollox - does a bb slip through the bucking lips OK ???

are the lips catching the bb, folding over causing jam/misfeeds ???

if the lips are tight you will struggle to get a bb to push through & chamber correctly

(can't be THAT tight - ergh yes they can, that tappet spring ain't that fucking strong)

 

 

 

somewhere in that vid it shows/explains how the bb is dropped in and MODERATELY pushed through to barrel/nub

can't remember where - it's in there somewhere

you should feel some SLIGHT resistance and require only MODERATE effort to push the bb through to barrel

(issue being that everybody's definition of "moderate" will vary slightly)

but you should not have to use much force at all, just enough that it doesn't fall in on it's own

and a mild light push it goes through the lips to barrel/nub

 

*** DO NOT GO MODDING THE HOP UNIT FFS ***

it was to show the tight bucking lip test, modding shit is very very very fucking rarely ever needed

(and only is such extreme rare cases, by confident people who can afford to fuck up a brand new hop)

 

if you have a bb catching on lips, or very tight entry/lips then expect feeding issues - even on slow/mild semi speeds

(on full auto at higher speeds - fuck all comes out)

 

People may sometimes say "it's firing two bb's at once"

in reality it is quite rare, usually it is misfeeding, partly loaded bb is then followed by another bb & 2 bb's appear exiting

 

normal operation on semi spamming...

 

1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 etc....

on bastid guns with feed issues....

1 - 1 - 0 - 2 - 1 - 0 - 1 - 1 - 0 - 2- 1 - 1 - 0 - 1 - 1 - 0 - 1 - 0 - 1

(the gun failed to feed a bb, sometimes it just missed & other times partly loaded-followed by another bb = 2 bb's at times)

 

So I'd pay close attention to the whole hop, bucking, barrel bollox you assembled

(another idea is to leave stock barrel/hop 100% as is, build new unit and if all goes to shit

then test with old barrel/hop combo still intact to diagnose where issue lies)

 

NOZZLE - ergh you did check/compare stock to new version length ???

coz if you used a nozzle too long you will struggle to feed

(and too short loses seal/power at bucking lips)

 

me thinks it is likely hop/bucking related

as some buckings in some hops really pinch and create a tight bb entry point for bb's to pass through

and yes even a mildly too tight bucking lip will restrict/impede feeding

(and is common issue if not checked with attention to detail when "upgrading" shit)

 

nozzle length is important too, if using the wrong length of nozzle

delay clip can help, but some are better than others in assisting nozzle retraction

the "delay" thing is a bit of a myth, in the way if you draw a nozzle back for longer

but only has 5.5mm clearance it won't allow a 5.95mm bb to feed

(so ultra long delay clips do fuck all if nozzle too long/tappet fin worn etc...)

 

here is a long delay clip...

 

 

if you use a nozzle too long you will still have feed issues no matter what

(and tight bucking lips/catching will still remain)

 

if you use a delay clip that is toooooo long, you will need to trim tappet fin in higher speed builds

but that is getting into timings n shit, point being it is about nozzle retraction than duration it is drawn back

(DSG builds for example have fuck all delay & can't fit delay clips, a sleeve is only real option for DSG's)

 

 

so the actual "delay" part is a bit of a myth (imho)

it is about ensuring you get the CORRECT nozzle retracting as much as possible

to allow ample space for bb to slip past & feed (with a decent mag)

but ensuring this,

will improve feeding even on mags with weaker spring tension in modest snappy guns too

 

best std delayers are these types...

 

https://www.ak2m4.co.uk/internal-parts/gears/zci-gear-delayer

 

bit of wafer thin extra material to retract nozzle a whisker further

but check in case tappet bottoms out on cylinder head at full 101% retraction

but best delayer type, might need a bit of work on some sectors but is best type imho

 

slapping shit together though in one go rarely goes perfectly as planned

so you need to go back check & investigate where issue is

(hop/bucking I reckon could be prime suspect)

[Kls77]

Vrc scar mags are pretty crap at feeding tbh . Try the modded sr25 mags . Feedd do much better . 

Or try the g+g sr 25 p mags . . Not the metal ones as there crap too 

Taiwan gun have the battleaxe SR25 for about £7 quid each . The need a little dremil or fileing but work great 

 

[paradoxum]

not all in one go but I will admit I never checked it after each mod / upgrade. I am thinking it has sometintg to do wit the feeding nozzle because other than that no idea.

[Sitting Duck]

16 minutes ago, paradoxum said:

not all in one go but I will admit I never checked it after each mod / upgrade. I am thinking it has sometintg to do wit the feeding nozzle because other than that no idea.

 

you built a complete Maxx hop, Madbull blue bucking with Lambda barrel...

so try the old stock hop/barrel combo

 

so I'd test for bb's passing through the Maxx hop setup

& if in doubt switch to old hop/barrel combo & test

 

simple process of elimination

if you got the red Maxx 38.4mm nozzle it "should" be correct length

as long it moves OK - not too trightly on cylinder head

it "should" operate OK etc...

 

test the bb passing through hop/bucking

& if crap - test old hop/barrel unit

[Adolf Hamster]

Did i just read maxx hop unit with madbull blue bucking?

 

I was gonna do an automotive analogy but i'm really struggling. Something about a lambo engine tied to a moped gearbox maybe?

 

 

 

[Iceni]

I'd say the air nozzle is too short or incorrectly seated on the tappet plate. I believe the VFC scar uses a different length nozzle to the standard M4 one, but you would have to compare old to new to be sure.

If you watch the hop unit it looks like a second BB is getting in, and or the air nozzle isn't moving on semi.

Could also be the tappet plate is binding on the gearbox or bushings if there's a slight incompatibility or a bushing that isn't seated fully. But the same effect could be seen with an air nozzle that is too short... so that would be my fist point of inspection.

 

[Sitting Duck]

I think you mean too long

it's a scar H with fatty mags & long mofo nozzle

than the scar L with m4 stuff

 

if OP has used the 38.4mm scar H nozzle with the Maxx scar hop it should be correct...

 

https://www.maxxmodel.com/cnc-aluminum-hopup-chamber-sv-vfc-scar-lh.html#:~:text=The Hopup Chamber SV unit is designed to accept the,losing FPS or dropping BBs.

 

deffo seems like a jumbo mofo nozzle for scar h...

 

 

a shorter nozzle feeds better

a longer nozzle (than req), feeds crap

 

SHS tappet should retract a whisker more than most tappets

but ridge where nozzle sits is not quite centred

meaning nozzle sits a fine whisker further back, hence why some lightly sand tappet front

but SHS tappet if anything sits half a whisker back (more retraction)

 

I think it is a classic case of changing WAY WAY WAY TOO MUCH IN ONE GO tbh

suffice to say some compatibility/tolerances have gone out the window

and due to lack of checking each component as it is replaced etc....

 

the issue(s) could lie in a number of places

but hop/bucking should be checked before tearing box open

(try old hop/barrel, coz reckon new maxx combo is a prime suspect)

1 hour ago, Adolf Hamster said:

Did i just read maxx hop unit with madbull blue bucking?

 

I was gonna do an automotive analogy but i'm really struggling. Something about a lambo engine tied to a moped gearbox maybe?

 

 

 

 

two grand spent, with madbull bucking etc... & it don't feed

ouch - I'd be pissed too

 

analogy - maybe this

 

 

 

or sprinkling glitter on something

[Adolf Hamster]

7 minutes ago, Sitting Duck said:

Two grand spent, with madbull bucking etc... & it don't feed

ouch - I'd be pissed too

 

Its kind of self defeating.

 

The maxx is a very, very good hop unit, if not the best then definately up there with the best when setup right (ie good alignment, correct nozzle, decent bucking, tight to the box etc)

 

But i dont think even that can overcome the handicap of a madbull rubber.

 

Whilst almost any of the options (prommy, pdi, stock tm, g&g green etc) would be better if you're running a maxx then it's gotta be a nice ml tan to spin up the heavies.

[Sitting Duck]

53 minutes ago, Adolf Hamster said:

 

Its kind of self defeating.

 

The maxx is a very, very good hop unit, if not the best then definately up there with the best when setup right (ie good alignment, correct nozzle, decent bucking, tight to the box etc)

 

But i dont think even that can overcome the handicap of a madbull rubber.

 

Whilst almost any of the options (prommy, pdi, stock tm, g&g green etc) would be better if you're running a maxx then it's gotta be a nice ml tan to spin up the heavies.

 

think the tight bucking lips from the madbull is looking to be an area which needs investigating

as said some buckings are a bit tight/pinchy in some hops

(had it myself & needed to rethink the barel/hop/bucking combo on more than one occasion)

 

yes at a push if tight apeture or lips, you could use a conical dremmel tool to widen/open it a whisker

but risky like any mod/bodge, but if up shit creek & understood risks of fucking it all up then yeah maybe

 

could just be a case of ramming the barrel too far into hop, that bucking lips protrude into feedtube

thus the exposed lips catch/fold over when attempting to feed/chamber the ammo...

had mega fat bucking all distorting as it is all assembled - yet pass the push test

& other times thinner buckings glide in smoothly but struggle to let bb's push through

(often it all goes together ok, but at times it is a PITA for niggly problems)

 

just slapping a long list of high end parts together means little if attention to detail is in short supply

(if you ain't checking, then you ain't really teching)

 

we've all been there though, learning from our many mistakes (wisdom)

[Adolf Hamster]

I just dont have a high opinion of madbull hop products, even moreso when the objective is a high end build.

 

I do agree here that this feels like a classic case of the difference between upgrading a gun, and filling it with expensive bits and expecting it to work better.

 

Granted from vfc's reputation i get the desire to replace all the internals straight off the bat, but you're absolutely correct that there's probably issues with tolerances going on, even a great part can fall flat if its not right for the build.

[DerDer]

Just to join the recommendations to look at the hop up. Many moons I had okay experiences with the Madbull but it was just one of the colours. As in the blue performed well but the red caused nothing but problems. Might have been vice versa with the colours.

 

The other thing is to look at the interaction between the  barrel and rubber. There have been reports of Lambda barrels cutting rubbers during installation. From what I understand it's primarily a problem with the .03 range but might be worth a look. 

 

Lastly fair play for actually posting this topic. Quite often you get people posting their buy lists but no feedback on how it went. 

[Sitting Duck]

On 21/12/2020 at 09:37, DerDer said:

Quite often you get people posting their buy lists but no feedback on how it went. 

 

Well - seems OP was making some progress

but a little feedback/update would help maybe ???

 

 

couldn't give a toss who is right/wrong

not even looking for a fanx to all who responded

more a case for others facing similar issues & seeing what helped/didn't help

 

understand it's chrimbo & lockdown crap

but an update at some point would be nice/courteous

 

congrats anyway making some progress to fix/resolve some issues with your gun