UK GBBR Tech

[yojimbo]

Can anyone recommend an exceptionally good, UK based, GBBR tech please?

Normally I do all my own work, but I am having a serious problem with one of my GBBR's which doesn't make sense and would appreciate someone who knows what they are doing to take a look?

Many thanks in advance.

 

[MistakenMexican]

IMO big Steve builds is one of the best around.

I’d like to think I’m pretty good, but Steve has fixed a pistol that I wrote off as boneyard on more than one occasion.

 

[EvilMonkee]

If its a GHK AK then I can help, otherwise good luck LOL

 

[yojimbo]

If its a GHK AK then I can help, otherwise good luck LOL

MWS Based

 

[Danhc92]

Whats the issue?

 

[yojimbo]

Whats the issue?

The hop seems to be adjusting itself. 
 

the cup seal on the nozzle seems to be causing excessive drag on the nozzle (yes properly lubricated)

occasionally an extra BB will just roll out of the barrel.

it is a toxicant spear, so MWS, but short bolt system. The first day I had it, it ran amasing, but the second day I fielded it I started getting issues with the hop and extra BBs falling out

Edit. The whole replica is stock, the only parts added were the barrel and bucking as the Toxicant don't supply these with the RIF.

 

[novioman]

Ian at Firesupport is excellent, probably about a six week turnaround though. Used BZ tactical recently, very proficient all round.

 

[SSPKali]

The hop seems to be adjusting itself. 
This could be the nozzle guide on the top of the bolt carrier rubbing the hop wheel as it moves forward. There should be a small scalloped section, try fettling that a bit and see if that sorts it.

the cup seal on the nozzle seems to be causing excessive drag on the nozzle (yes properly lubricated)

Some cup seals do that, the Dynamic Precision green ones are great and don’t do this.

occasionally an extra BB will just roll out of the barrel.

This is likely due to the hop being turned off by the nozzle guide. When the BB is chambered there isn’t enough friction to hold it and it rolls out. Tackle this issue last if it is still occurring.

 

[yojimbo]

The hop seems to be adjusting itself. 
This could be the nozzle guide on the top of the bolt carrier rubbing the hop wheel as it moves forward. There should be a small scalloped section, try fettling that a bit and see if that sorts it.

Hi, thank you for taking the time to reply. On the photo I have attached, can you please indicate what I need to remove please? I would really appreciate it.

Many thanks in advance.

View attachment 146914

 

[SSPKali]

The part circled in red is the cut out for the hop up wheel.

To make more room you can either carefully file out some more or make the bolt carrier and nozzle guide run “lower” in the upper receiver. Hao achieves this with their BCG stickers for example.

View attachment 146917

 

[yojimbo]

The part circled in red is the cut out for the hop up wheel.

To make more room you can either carefully file out some more or make the bolt carrier and nozzle guide run “lower” in the upper receiver. Hao achieves this with their BCG stickers for example.

Are you talking about putting stickers in the bottom of the charging handle or in the upper where the charging handle sits?

If I file out the are you marked with the red circle, are we talking a 1 or 2 mm or more of a chunk?

(p.s. is this something you have experienced before)

Thank you again 

 

[SSPKali]

Are you talking about putting stickers in the bottom of the charging handle or in the upper where the charging handle sits?

If I file out the are you marked with the red circle, are we talking a 1 or 2 mm or more of a chunk?

(p.s. is this something you have experienced before)

Thank you again 

Hao put the sticker on the upper left face of the BCG (opposite side to the ejection port) 

it probably needs less than 1mm removing, best to take a little off and try rather than going mad with the angle grinder!

I have experienced it with certain combinations of nozzle guides and charging handles. The old worn TM guide and handle was bad for it. Once replaced and the sharp edge taken off the cut out I have had zero issues

 

[yojimbo]

Hao put the sticker on the upper left face of the BCG (opposite side to the ejection port) 

it probably needs less than 1mm removing, best to take a little off and try rather than going mad with the angle grinder!

I have experienced it with certain combinations of nozzle guides and charging handles. The old worn TM guide and handle was bad for it. Once replaced and the sharp edge taken off the cut out I have had zero issues

This area in highlighted with the white square is called the nozzle guide?

Thinking back, I had seen someone mention something about the gas key at the top of the bolt wearing and sometimes causing problems with the bolt height. I think it was on one of Ollie Talks airsoft videos, rip. 

Thank you again so much for your suggestions, will only take off a bit at a time and see what happens. Definitely a file and not angle grinder job lol

View attachment 146918

 

[SSPKali]

I think the “gas key” is the nub at the top of that part that fits in the underside of the charging handles. Obviously there are slight differences between the firearm and airsoft M4 designs so not a direct comparison ?

 

[ButcherBill]

Please be wary about taking too much off, I don't see any wear on the bolt carrier, if anything was rubbing there would be signs.

 

[SSPKali]

Please be wary about taking too much off, I don't see any wear on the bolt carrier, if anything was rubbing there would be signs.

It probably won’t wear the nozzle guide much as it will naturally roll the hop wheel and not scrape across it.

A non-destructive way of testing would be to put a long strip of gaffer tape in the channel in the upper receiver that the charging handle runs in. That will move the bolt down a hair and may stop the issue. Then at least you know the likely cause and can always peel the tape out after testing.

 

[Mad dog 49]

I had this issue with the Noveske N4. Tried filing as directed above but the hop still wound itself off after a few mags. I solved it once and for all by ditching the stock hop adjuster for an archwick tdc one.