Inconsistent hop

[Pewpewpetie]

Hi all, have an m4 I'm having issues with the hop. I have tried everything from standard prommy purple, maple leaf and s hop, all do the same.. I have a consistent 330/331fps on 0.2g but every shot is different, the bbs fly perfectly straight but the vertical action of the bbs changes every shot, some go 6ft higher then others, what could be causing these random shots? Could nozzle length affect this? Can't think what else would cause this. I've also tried different hops, standard cyma, zci and a prowin

Or could it be a tappet plate problem not resetting the bb in correct place on each shot?

[Rogerborg]

Hmm, that is curious, you've covered most things that I'd have suggested: energy consistency, hop unit, and hop rubber.  Airsoft gnus aren't that complicated, it's just puff, spin and point.

 

Is the energy really consistently consistent?  Prowin, meh, but if that's a ZCI rotary hop, I wouldn't expect issues with it.

 

If puff and spin are consistent, the only thing that leaves is point, i.e. the barrel.  Given what you've already done, I'd assume you've cleaned the barrel as well and had a look down it for obvious imperfections?

 

You could sling in one from your MP5 or AK and see if it's more consistent (even at a different energy), or ZCI or AOLS are both decent choices for not much money.

 

 

[Pewpewpetie]

24 minutes ago, Rogerborg said:

Hmm, that is curious, you've covered most things that I'd have suggested: energy consistency, hop unit, and hop rubber.  Airsoft gnus aren't that complicated, it's just puff, spin and point.

 

Is the energy really consistently consistent?  Prowin, meh, but if that's a ZCI rotary hop, I wouldn't expect issues with it.

 

If puff and spin are consistent, the only thing that leaves is point, i.e. the barrel.  Given what you've already done, I'd assume you've cleaned the barrel as well and had a look down it for obvious imperfections?

 

You could sling in one from your MP5 or AK and see if it's more consistent (even at a different energy), or ZCI or AOLS are both decent choices for not much money.

 

 

Yes I've even tried different barrels, the only other thing I was thinking is could the nozzle not be setting each bb correctly between shots

2 minutes ago, Pewpewpetie said:

Yes I've even tried different barrels, the only other thing I was thinking is could the nozzle not be setting each bb correctly between shots

Or although it feeds flawlessly could nozzle length cause this, maybe nozzle is pushing to far into hop and pushing the hop arm? I'm really out of ideas

[Pewpewpetie]

1 hour ago, Rogerborg said:

Hmm, that is curious, you've covered most things that I'd have suggested: energy consistency, hop unit, and hop rubber.  Airsoft gnus aren't that complicated, it's just puff, spin and point.

 

Is the energy really consistently consistent?  Prowin, meh, but if that's a ZCI rotary hop, I wouldn't expect issues with it.

 

If puff and spin are consistent, the only thing that leaves is point, i.e. the barrel.  Given what you've already done, I'd assume you've cleaned the barrel as well and had a look down it for obvious imperfections?

 

You could sling in one from your MP5 or AK and see if it's more consistent (even at a different energy), or ZCI or AOLS are both decent choices for not much money.

 

 

I've got an adjustable nozzle so I'll try that and see if length has anything to do with it. My only guess is that the nozzle is sealing fine but is slightly too short , meaning bbs aren't being seated correctly or consistently

[Rogerborg]

56 minutes ago, Pewpewpetie said:

I've got an adjustable nozzle so I'll try that and see if length has anything to do with it. My only guess is that the nozzle is sealing fine but is slightly too short , meaning bbs aren't being seated correctly or consistently

 

I can't think of anything else either, although I'd expect to see some variation in muzzle energy in that case. Same with the hop unit not being pushed back against the gearbox hard enough, and having tried three units that's unlikely to be it either.

 

I'm guessing that you've also tried different mags, just on the off-chance that you've got one that's barely managing to lift the BBs up to the chamber.  Although they should either feed, or not feed, and then the nozzle should seat them.

 

Is the inner barrel fairly tight within the outer?  Tried packing it with tape?  Although (I'm using that word a lot!) I'd be surprised to only see vertical play and not horizontal.

[Pewpewpetie]

12 minutes ago, Rogerborg said:

 

I can't think of anything else either, although I'd expect to see some variation in muzzle energy in that case. Same with the hop unit not being pushed back against the gearbox hard enough, and having tried three units that's unlikely to be it either.

 

I'm guessing that you've also tried different mags, just on the off-chance that you've got one that's barely managing to lift the BBs up to the chamber.  Although they should either feed, or not feed, and then the nozzle should seat them.

 

Is the inner barrel fairly tight within the outer?  Tried packing it with tape?  Although (I'm using that word a lot!) I'd be surprised to only see vertical play and not horizontal.

Inner barrel stability is great, I'll try the adjustable nozzle maybe and see if it's ever so slightly short and thus not correctly seating each bb the same

[Pewpewpetie]

34 minutes ago, Rogerborg said:

 

I can't think of anything else either, although I'd expect to see some variation in muzzle energy in that case. Same with the hop unit not being pushed back against the gearbox hard enough, and having tried three units that's unlikely to be it either.

 

I'm guessing that you've also tried different mags, just on the off-chance that you've got one that's barely managing to lift the BBs up to the chamber.  Although they should either feed, or not feed, and then the nozzle should seat them.

 

Is the inner barrel fairly tight within the outer?  Tried packing it with tape?  Although (I'm using that word a lot!) I'd be surprised to only see vertical play and not horizontal.

Right tried adjustable nozzle increasing length by 0.1mm each time , still same problem. I did notice a fluctuation in fps but again it's a strange one . These are the reading from chronoing with 0.28g asg devil bbs.( Don't have any 0.2g to test with)

1-278fps

2-278fps

3-277fps

4-276fps

5-279fps

6-278fps

7-262fps

8-275fps

9-278fps

10-275fps

 

as you can see it's relatively consistent apart from shot 6 which was 262fps.

[Pewpewpetie]

Also maybe, could it be a bad batch of bbs, usually the asg devil's have been good. I'll order some Geoff 0.3g on Friday and see if this changes anything

[Rogerborg]

6 hours ago, Pewpewpetie said:

Also maybe, could it be a bad batch of bbs

 

Honestly, I'm struggling to think of what else it could be, you've ruled out all the other factors. I'm fascinated to find out.

[Lozart]

On 21/09/2021 at 08:26, Pewpewpetie said:

Hi all, have an m4 I'm having issues with the hop. I have tried everything from standard prommy purple, maple leaf and s hop, all do the same.. I have a consistent 330/331fps on 0.2g but every shot is different, the bbs fly perfectly straight but the vertical action of the bbs changes every shot, some go 6ft higher then others, what could be causing these random shots? Could nozzle length affect this? Can't think what else would cause this. I've also tried different hops, standard cyma, zci and a prowin

Or could it be a tappet plate problem not resetting the bb in correct place on each shot?

 

Could it be the adjustable nozzle not properly sealing? Might be some airloss through the threaded portion - try putting some silicone grease on the threads and see if that makes a difference.

[Pewpewpetie]

On 22/09/2021 at 12:07, Lozart said:

 

Could it be the adjustable nozzle not properly sealing? Might be some airloss through the threaded portion - try putting some silicone grease on the threads and see if that makes a difference.

No, I only used the adjustable nozzle to measure correct size then I replace with one of that measurement

[Rogerborg]

As far as I can see, that only leaves a barrel swap.  Is it a particularly wide or narrow bore in there?

[AirSniper]

Back to basics...

1. Clean the barrel.

2. Wind the hop up back to minimum then try adjusting to get desired result.

My sons G&G GC16 had issues, the hop up and dirt were the problems that was causing inconsistent shot placement.

Once cleaned and adjusted, problem solved.

 

[Asomodai]

Is there any residue on the inside of the outer barrel or flash hider? This happens on my FN57 pistol as the opening on the aftermarket barrel is too narrow and I occasionally get fliers. 

[heroshark]

It bad JuJu, you need to perform a shamanic ritual. Have you got any animals that you could use as a sacrifice?

[Pewpewpetie]

Right so , still no joy, I've tried a different barrel (standard and a zci) all are doing the same. I think it's time to give up, I do have a 3 fps deviation but I can't imagine that 3 fps would cause this. These are Chrono readings on 0.28g asg. Going to try playing with the hop arm as this is literally the only thing left, my last guess is that there is some vertical play on the arm causing different pressure to be applied each shot

20 hours ago, Asomodai said:

Is there any residue on the inside of the outer barrel or flash hider? This happens on my FN57 pistol as the opening on the aftermarket barrel is too narrow and I occasionally get fliers. 

No residue anywhere, barrel is clean, tried new r hop patch, g&g green , prommy purple and a selection of nubs and still get it. It has to be the hop arm, some kind of vertical movement

20 hours ago, heroshark said:

It bad JuJu, you need to perform a shamanic ritual. Have you got any animals that you could use as a sacrifice?

Yeah tried shooting the cat but bb curved hahahahahah( I didn't really)

[heroshark]

1 hour ago, Pewpewpetie said:

Yeah tried shooting the cat but bb curved hahahahahah( I didn't really)

I can hook you up with a good shamen who will bring all the kit. You just need to wire $563.98 to my representative in Uganda.

[Rogerborg]

14 hours ago, heroshark said:

I can hook you up with a good shamen who will bring all the kit. You just need to wire $563.98 to my representative in Uganda.

 

I'd take that offer, I think it's the only realistic option left at this point.

[Pewpewpetie]

4 hours ago, Rogerborg said:

 

I'd take that offer, I think it's the only realistic option left at this point.

In considering hahhaha

[heroshark]

For a straight $1000 he'll throw in a curse to smite your enemies.

[Pewpewpetie]

Believe at last I have figured it out, the cylinder/piston head. I believe the o ring was to thick. Was creating a great seal, but wasn't allowing the ported piston head to vent on retraction, which then created a slight suction in barrel. So my guess is, if that bb hasn't left the barrel completely by the time the piston begins retracting then some of the air being used to propel the bb will be sucked back into the cylinder. Will be testing later once the winds and rain stop

[Pewpewpetie]

Also I have noticed that the piston isn't returning to exactly the same spot after each shot on semi.

[Lozart]

Are you running a cycle completion mosfet or precocking based on time?

[Pewpewpetie]

17 minutes ago, Lozart said:

Are you running a cycle completion mosfet or precocking based on time?

No, basic mechanical trigger, 7.4v 25c  lipo,22tpa high torque motor with 13:1 gears, AOE corrected and sector delay switch

Edited September 27, 2021 by Pewpewpetie

[Lozart]

5 minutes ago, Pewpewpetie said:

No, basic mechanical trigger, 7.4v 25c  lipo,22tpa high torque motor with 13:1 gears, AOE corrected and sector delay switch

 

That'll be your problem then.