Ak M249 Not Firing

[Ben Savage]

Hello all, more gun problems unfortunately....

A couple of weeks ago a group of us went to a game, and in the lead up my mate's M249 had been functioning perfectly, but when we got to the game, we put the battery in (9.6V 1600mAh NiMH), and the gun would not fire. We tested with all of our batteries, before ruling these out as the problem.

 

When the trigger is pulled, there is no sound from the gun except for the 'click' sound which is made when the trigger is pulled. The wires get warm extremely quickly, and no electrical sound is made from any part of the gun.

We had an idea it could be the fuse, so after ordering a box of fuses, I then realised that I foolishly bought fuses which are too small to fit , but we managed to test these fuses still, and it did not change anything unfortunately.

 

If anybody has any idea what can be done to fix this, it would be great, thanks.

[Rogerborg]

Hot wires mean power is getting to the motor.  It's likely locked up with the spring under compression, and the motor armature lined up with the permanent magnets (I can science, me) so that there's not enough torque to get it moving any further.  However, it will still draw more current than when it's spinning, so don't keep trying to free it up with trigger pulls and don't bypass the fuse. Cheaper to replace that than the motor!

 

That's the theory. In principle we'll have to wait for someone who knows the practice to tell you if there's an easily accessible anti-reversal latch release on the M249 that will make this a 10 second job, or whether you're looking at disassembly to get to it.  Sorry, a quick Googling doesn't turn anything up.

[DerDer]

Might be worth trying to replace the microswitch? They are fairly cheap. 

[Rogerborg]

1 minute ago, DerDer said:

Might be worth trying to replace the microswitch? They are fairly cheap. 

 

Why?  The wires are hot.

 

The cost is in time, to see if it's locked up under compression, and if so release the ARL.

[DerDer]

15 minutes ago, Rogerborg said:

 

Why?  The wires are hot.

 

The cost is in time, to see if it's locked up under compression, and if so release the ARL.

Based on experience with the quality of some of the microswitches in airsoft. If you're opening up the gearbox ( admittedly not too bad on 249) it's one candidate to replace.  Particularly if plan on running higher capacity batteries.   

[Nick G]

Most 249 boxes are very easy to remove the spring. Take it out and see if the motor will spin , then replace the spring. hopefully the piston will move to a different position and things will be back to normal. 

[Rogerborg]

5 hours ago, Nick G said:

Most 249 boxes are very easy to remove the spring. Take it out and see if the motor will spin , then replace the spring. hopefully the piston will move to a different position and things will be back to normal. 

 

Ah! Good call.  Looks like it's a dead simple quick-change:

 

 

[Ben Savage]

20 hours ago, Nick G said:

Most 249 boxes are very easy to remove the spring. Take it out and see if the motor will spin , then replace the spring. hopefully the piston will move to a different position and things will be back to normal. 

 

14 hours ago, Rogerborg said:

 

Looks like it's a dead simple quick-change:

 

Thanks that has done the trick, relieved it was such an easy fix.

[Rogerborg]

Ace, great to hear it wasn't anything serious.  That's a pretty smart spring change system too.

[Nick G]

Excellent result . That spring change system is awesome isn't it !

[AdamMD7]

I've just had the same issue on the MK46 and the advice here has fixed it! So, thank you everyone!

[Rogerborg]

5 hours ago, AdamMD7 said:

I've just had the same issue on the MK46 and the advice here has fixed it! So, thank you everyone!

 

Great to hear that, and it's always a pleasant surprise when something in airsoft turns out to be as easy as it should be, rather than as hard as it could be.