B&T MP5 issue with feeding

[Bobbybrown]

Hi all 

Just got my first battery MP5 yesterday, only mark I can see on it is “B&T”.

issue I’m having is it doesn’t feed, if I drop the BB down the barrel it’ll shoot it out, it doesn’t take them from the mag despite the mag appearing to work as it should.

I’ve stripped it down and the gearbox(?) that connects to the hop up unit and the barrel appears to maybe be the issue.

I am assuming the small pipe on the end of the gearbox that connects to the hop up is supposed to go in and out when it shoots, to allow the next BB to load, this isn’t happening. 

Is this supposed to move in and out when being fired? And if so, any recommendations what I can do to repair it so it does? I haven’t fully stripped an AEG before so it’s new territory for me, but if there is something specific you need to be able to see in order to help I’ll do my best to get to that part and photograph it.

for now, this is the “pipe” I’m talking about.

many thanks.

View attachment 93639

 

[Nick G]

The bit circled in blue is the loading nozzle and it should indeed move back and forth as the gearbox cycles.  Is the gun new ? if so probably easiest to send it back. If you want to fix it yourself though you are going to have to open up the gearbox as the nozzle is moved by the tappet plate which is internal. May have popped off or there may be a damaged part.

If you havn't opened a gearbox before then get yourself onto youtube and watch a few videos first, also watch a coupke about stripping down an MP5 as they are different to an M4 and indeed there are several methods of strip down for MP5's so have a hunt for a video that matches your model.

 

[Floperator]

Should those wires be sitting there in the magwell between the mag and nozzle?

Did you buy this new or 2nd hand?

 

[colinjallen]

The nozzle should move, as it should be connected to the tappet plate.

Where did you buy it?  From a shop or from a private seller?

 

[Bobbybrown]

From a private seller, wasn’t able to check it properly but dry fired it and it was fine, wasn’t in a position to be able to cycle bbs through it sadly. Regretting that now.

I’ve had it in bits today and put it back together to make sure it’s nothing obvious. Still the same. I think I’ll need to get the gearbox open as you guys have said and see what I can see in there.

Would it be easier to replace the gearbox? I suppose then the question of suitable replacements pops up.

Should those wires be sitting there in the magwell between the mag and nozzle?

Did you buy this new or 2nd hand?

I had started stripping it at the point I took the photo so I think that’s why they are so obvious in the photo as I had moved things around 

 

[colinjallen]

From a private seller, wasn’t able to check it properly but dry fired it and it was fine, wasn’t in a position to be able to cycle bbs through it sadly. Regretting that now.

I’ve had it in bits today and put it back together to make sure it’s nothing obvious. Still the same. I think I’ll need to get the gearbox open as you guys have said and see what I can see in there.

Would it be easier to replace the gearbox? I suppose then the question of suitable replacements pops up.

I had started stripping it at the point I took the photo so I think that’s why they are so obvious in the photo as I had moved things around 

There are lots of videos that will show you how to open and work on a gearbox; use this as a learning experience.  That nozzle should be attached to a long piece of plastic inside the gearbox; this is called the tappet plate and its job is to move the nozzle backwards and forwards.

Where are you based?

 

[Bobbybrown]

I’m in Tamworth.

To be honest I’ve wanted to strip one down for some time, I have other aegs but I’ve never taken one apart so I quite enjoyed taking it all to bits and reassembling, sure I’ll enjoy it even more if it works afterwards ?

 

[Bobbybrown]

We have progress!

gearbox opened and I’ve found this broken piece. The only details on the gear is CA-SL.

Can anyone tell me the name of this gear so I can try to find a replacement please?

Thankyou 

View attachment 93718
 

I think it might be called the sector gear but an online search doesn’t show any exactly the same, are they all the same size? 

 

[colinjallen]

We have progress!

gearbox opened and I’ve found this broken piece. The only details on the gear is CA-SL.

Can anyone tell me the name of this gear so I can try to find a replacement please?

Thankyou 

View attachment 93718
 

I think it might be called the sector gear but an online search doesn’t show any exactly the same, are they all the same size? 

That would explain it!  That piece pushes the tappet plate back, allowing a BB to feed.

It is indeed the sector gear, but you would probably be best advised to buy a whole new 16:1 gearset from someone like AK2M4 (allegedly, other purveyors of airsoft bits and pieces do exist), along with a delayer chip to ensure that the tappet plate stays back long enough.

Whatever you do, you are going to have to do some shimming to ensure that the gears are spaced properly.  There are some very good guides to this online.

 

[Bobbybrown]

That would explain it!  That piece pushes the tappet plate back, allowing a BB to feed.

It is indeed the sector gear, but you would probably be best advised to buy a whole new 16:1 gearset from someone like AK2M4 (allegedly, other purveyors of airsoft bits and pieces do exist), along with a delayer chip to ensure that the tappet plate stays back long enough.

Whatever you do, you are going to have to do some shimming to ensure that the gears are spaced properly.  There are some very good guides to this online.

Good, I’m going to need every guide I can find.

also had a look at a drop in replacement but will keep looking. I’ll check out the 16:1 gear sets and see what I can find. Would love to get this thing up and running before I forget how it goes back together ?
 

Is there a way to know the ratio of the gears in there at the moment? Are they likely to be 16:1 or could they be some other ratio.

Off to YouTube to check out videos on shimming 

 

[colinjallen]

They are most likely 18:1; you can check the ratio by counting the teeth on each one and working out the ratio that way.

 

[Lozart]

Is there a way to know the ratio of the gears in there at the moment? Are they likely to be 16:1 or could they be some other ratio.

Off to YouTube to check out videos on shimming 

They are most likely 18:1; you can check the ratio by counting the teeth on each one and working out the ratio that way.

As above, standard gear ratios are usually 18:1. 16:1 will make your gun run faster (not loads more but even so). These are very good https://www.ak2m4.co.uk/internal-parts/gears/zci-gear-set-advanced-18-1 these are at the very least better than the ones that are in there right now https://www.ak2m4.co.uk/internal-parts/gears/shs-18-gearset

Set of shims https://www.ak2m4.co.uk/zci-shim-set?search=shim (do your research on YouTube and TAKE. YOUR. TIME.)

Get some decent lube and clean the gearbox out while you're at it.

Gear lube: https://www.amazon.co.uk/Abbey-Shotgun-Airsoft-Spring-Molybdenum/dp/B071FYQGLJ/ref=pd_lpo_3?pd_rd_i=B071FYQGLJ&psc=1

Seals and piston rings etc https://www.amazon.co.uk/Abbey-Silicone-Grease-Gun-Maintenance/dp/B00LHTIH7G

Degreaser (for cleaning) https://www.halfords.com/motoring/engine-oils-and-fluids/engine-cleaner-and-degreaser/halfords-engine-and-parts-degreaser-500ml-621525.html

 

[Bobbybrown]

Tremendous! Thankyou for that and the links, that’s super helpful.

I’ll have a look at those and get some orders in 

 

[Bobbybrown]

Gearset and shims should arrive today so fingers crossed I can figure it out. I’ll update when I’ve got some news 

 

[Bobbybrown]

Having some trouble getting the gearbox back together, given up for tonight will try again tomorrow. The smaller piece on the bottom left (think it’s a stop for the wrong way?) has moved so I need to figure out how it was in the first place.

Will battle on tomorrow, asked a friend who’s had airsoft in the past if he knew how to do it as he’s the only person in Tamworth that I know, that has airsoft but alas he hasn’t got a clue! Shame ?

 

[Shamal]

I think you mean the anti reversal latch? Got a fine spring on it? 

Have a look at some pics on Google. That will show you the orientation of it.

It can be a pain to get it to stay in place. 

Good luck.?

 

[Bobbybrown]

I think you mean the anti reversal latch? Got a fine spring on it? 

Have a look at some pics on Google. That will show you the orientation of it.

It can be a pain to get it to stay in place. 

Good luck.?

That’s the one 

 

[Shamal]

That’s the one 

Yeah. Just Google it mate.

I think you can use something really thin like feeler blades to hold it down while you offer up the top half of shell.

?

Regards 

 

[Speedbird_666]

A strong magnet usually works to hold the Anti-Reveral latch in place.

Put the magnet on the underside of the left receiver shell (the side where the gears are placed when assembling) over the hole where you insert the ARL. Makes life a lot easier.

 

[Bobbybrown]

Thanks for the advise guys. Really appreciate the help