Gearbox Lock Up On Semi?

[JRTIGHE]

Hi all,

 

Just noticed my M&P15 sometimes has a gearbox lock up on semi if I I'm trying to fire rapidly and I don't quite pull the trigger all the way back. It's like the gearbox starts to operate but doesn't fully cycle, and gets stuck mid cycle then won't start again unless I go onto full auto.

 

Not a big problem, just wondering how it would be fixed as I usually stick to semi but I have a fast trigger finger.

 

Thanks.

 

[deldalton]

Hi all,

 

Just noticed my M&P15 sometimes has a gearbox lock up on semi if I I'm trying to fire rapidly and I don't quite pull the trigger all the way back. It's like the gearbox starts to operate but doesn't fully cycle, and gets stuck mid cycle then won't start again unless I go onto full auto.

 

Not a big problem, just wondering how it would be fixed as I usually stick to semi but I have a fast trigger finger.

 

Thanks.

When the gearbox "locks up" what happens when you pull on the trigger, in semi? What noises, if any, do you hear (including those from the trigger mechanism)? Does it sound like everything is working correctly, apart from the fact that the motor isn't running?

[JRTIGHE]

I don't believe it's that the motor isn't running. There's literally no noise, like the whole system isn't working. When I pull the trigger it's as if I'm on safe. When I switch to auto, it remedies itself instantly.

[deldalton]

I don't believe it's that the motor isn't running. There's literally no noise, like the whole system isn't working. When I pull the trigger it's as if I'm on safe. When I switch to auto, it remedies itself instantly.

Just to clarify, you can't pull the trigger at all (in semi) when this happens?

 

If that's the case, perhaps it is actually in safe? I had a similar issue with my G36. Turned out the selector switch was intereferring with the control plate. I identified it by just nudging the selector switch towards full-auto (only slightly, so that it's still actually in single) and it started working. A little adjustment to the selector switch and the problem was solved.

 

What makes your example similar to the problem I had is that in full-auto there wasn't a problem. But, this was because the control plate was moved completely out of the way and could no longer interfere.

 

 

It may be a completely different problem in your case, and I can't say I'm familiar with the layout of the M&P-15, but it's just a thought.

[Hudson]

It's just one of those things unfortunately; due to the design of gearboxes.
There's things you can do to reduce & minimise it; but you'll never get rid of it completely. (Higher voltage battery, high speed gears might help).

It's caused by spamming the trigger too much on semi, releasing the trigger before it's performed a full cycle, so necessitating switching to f/a before you can fire again.
Make sure you pull the trigger FULLY back, and try to slow down a little bit if possible!

[JRTIGHE]

It's just one of those things unfortunately; due to the design of gearboxes.

There's things you can do to reduce & minimise it; but you'll never get rid of it completely. (Higher voltage battery, high speed gears might help).

 

It's caused by spamming the trigger too much on semi, releasing the trigger before it's performed a full cycle, so necessitating switching to f/a before you can fire again.

Make sure you pull the trigger FULLY back, and try to slow down a little bit if possible!

This is exactly what I'm doing! I guess I will just have to slow down a bit - I'm so used to my M14 with which I can just spam my trigger. I didn't realise how responsive it is!

[jcheeseright]

it's 'fixable' with an active braking mosfet, though best fix i simply to get a higher voltage battery. You'll find that as your batteries get flatter it'll happen more and more often.

[two_zero]

 

It's caused by spamming the trigger too much on semi, releasing the trigger before it's performed a full cycle, so necessitating switching to f/a before you can fire again.

Make sure you pull the trigger FULLY back, and try to slow down a little bit if possible!

joykill.

 

 

it's

'fixable' with an active braking mosfet, though best fix i simply to

get a higher voltage battery. You'll find that as your batteries get

flatter it'll happen more and more often.

that's better!

[JRTIGHE]

it's 'fixable' with an active braking mosfet, though best fix i simply to get a higher voltage battery. You'll find that as your batteries get flatter it'll happen more and more often.

Actually, thanks for reminding me about the batteries! I'm using a 7.4v LiPo, which I haven't charged since I got it from the previous owner... which means it could be in any state! I'll charge it tomorrow (making sure to watch it so it doesn't burn the house down...).

 

I was looking at AB MOSFETs actually, to try and improve trigger response (which I don't believe is very good - although that might be down to the battery!). How easy are they to install? What are people's thoughts on this one? All eBay reviews look perfect:

 

http://www.ebay.co.uk/itm/AirFET-MOSFET-airsoft-AEG-switch-with-passive-brake-FREE-PAIR-OF-DEANS-/190822336134?pt=UK_SportingGoods_Hunting_ShootingSports_ET&hash=item2c6de5c686

[jcheeseright]

I can't comment on the ease of install for a MOSFET as I've never done one myself, but I've seen lots of people who are borderline retarded install their own so it can't be that hard!

[Ian_Gere]

There are plenty of plug'n'play MOSFETs, Joe. You just choose which connectors you want on it and plug it in where you would plug your battery in, then plug your battery into it. But to get the full benefit of them you want the type which either must or can be soldered in with one or two additional thin wires.

 

They come with instructions so simple that, as James says, a fcuking idiot could follow them. You just need a soldering iron and to watch a youtube vid or two on soldering...

 

(which can be summed up as: 'tin' your wires 1st, which means soak the bare copper with a bit of molten solder so it becomes a shiny pin; heat the metal you are going to solder to, not the thing you are soldering on; touch the 'tinned' wire to the hot metal next to the iron tip; it should melt; take the iron away while holding the wire in place and it will solidify; the joint should be shiny; if it isn't, reapply the iron tip briefly on top of the joint as you touch more solder to the wire; take the iron away while holding the wire in place {a bit of good finger dexterity is all this holding 3 things needs but, if you're going to do it a few times, some kind of clamp is best}; it should now be a shiny blob; it's good practice to try to avoid large blobs of solder on your joints because they become the cause of inductance and capacitance problems in sensitive circuitry, but in this application you needn't worry about it, just so long as the joint is on there firmly and shiny; also try to avoid heating components for longer than necessary, so if you fcuk it up, let it cool down before you have another go.)

 

Thing is mate, if you're looking at spending £20 on one, it might be better to spend an extra tenner and get a Burst Wizard King Kong from Airsoft World so you'll have all the bells and whistles

[JRTIGHE]

There are plenty of plug'n'play MOSFETs, Joe. You just choose which connectors you want on it and plug it in where you would plug your battery in, then plug your battery into it. But to get the full benefit of them you want the type which either must or can be soldered in with one or two additional thin wires.

 

They come with instructions so simple that, as James says, a fcuking idiot could follow them. You just need a soldering iron and to watch a youtube vid or two on soldering...

 

(which can be summed up as: 'tin' your wires 1st, which means soak the bare copper with a bit of molten solder so it becomes a shiny pin; heat the metal you are going to solder to, not the thing you are soldering on; touch the 'tinned' wire to the hot metal next to the iron tip; it should melt; take the iron away while holding the wire in place and it will solidify; the joint should be shiny; if it isn't, reapply the iron tip briefly on top of the joint as you touch more solder to the wire; take the iron away while holding the wire in place {a bit of good finger dexterity is all this holding 3 things needs but, if you're going to do it a few times, some kind of clamp is best}; it should now be a shiny blob; it's good practice to try to avoid large blobs of solder on your joints because they become the cause of inductance and capacitance problems in sensitive circuitry, but in this application you needn't worry about it, just so long as the joint is on there firmly and shiny; also try to avoid heating components for longer than necessary, so if you fcuk it up, let it cool down before you have another go.)

 

Thing is mate, if you're looking at spending £20 on one, it might be better to spend an extra tenner and get a Burst Wizard King Kong from Airsoft World so you'll have all the bells and whistles

Lucky, I already have some experience with soldering. Finally my two *wasted* years of GCSE Electronics should come in useful! I'll take a look at the King Kong, thanks!

[Airsoft-Ed]

Ah GCSE Electronics, the worst choice I ever made. I do love getting Ds because of teacher ineptitude.

 

I'd say the easiest thing to do would be get a new, stronger motor, fit a weaker spring and get a tightbore so you don't lose much in terms of fps, or upgrade your batteries to 9.9v LiFes/11.1v LiPos.

 

Or you could do all 4 like I've done.

 

I can spam my L85 as much as I want and it's almost impossible to semi jam it.

[Unrustle_Thine_Jimmies]

I've done what Ed has done minus the tightbore on my project gun.While you are taking apart the gearbox may as well check the shimming and re-shim if necessary. Bad shimming causes plenty of problems.

[TPI]

I think it's Funny that Ed couldn't Install his ASCU V2 and your all saying a Numpty could do it ROFLMAO

[JRTIGHE]

Just as an update to this thread: I've recharged the LiPo and the trigger response has drastically improved, as well as the rate of fire. I've tried spamming the trigger and I've only had 1 lock up so far so I believe the only issue was low battery power. Overall I'm extremely happy with the gun, now I'll just have to skirmish it!