is this a new CA 249 or one that's been sitting for a while?
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edit:
On a somewhat related note to the mosfet comments previously about trigger contact pins falling out... While a mosfet can't prevent components from shitty manufacture coming apart... they can prevent this:
The gun is a CA g36 running on a CA red motor, seems to be a stock gearset, shimmed reasonably well, shooting about 380-390. This gun is a teammate's gun. He doesn't play that often, only when we do private club games with our family and friends and when we gather to do nightfall. This gun was used as a support gun, firing full auto. Previous to NF3, it was used in NF2 and again in a game in the fall. So not a huge number of rounds through it.
No mosfet, was fused until beginning of NF3 when we discovered the fuse was ... well fused. (Thanks to the guys at I think niagara quartermaster for the crimp terminal) We were able to put it back together and run it for NF3.
Owner gave it over to me to rewire in the off season to get rid of the crimp connector. It looked like a stock wiring harness in silver wire, it wasn't crappy wire, but it wasn't awesome wire, but the harness itself was good, no melted points no nothing, so even mediocre wiring can hold up to what I'm about to show.
We powered this gun with a fairly large 7.4 lipo, something like a 50C 2300mah brick rear wired in a KV stock. The intent was to have enough power to drive the motor without danger of overdrawing the battery, on top of having a good mah reserve so the battery would last a while into the game as a support gun. Low internal resistance of the battery would mean it won't heat up as much when under constant or extreme load.
So fastfoward to this weekend, I decided I had time to open it up to rewire it in milspec alpha wire. Only to discover that the screw holding one of the contacts in place would not budge. It stripped and resisted all attempts to be undone.
Then I looked at the contacts.
lol. Initially I saw the 1 tab sitting much lower than the other one.
WAT.
Looking closer, you see the base of the fins at the housing is melted as well.
So I cut off the whole thing and put in a new housing and contacts into the gun and away it went.
Further autopsy on the contacts
Looks alright from here, aside from the screw that wouldn't budge.
Cutting the plastic from around the screw I grabbed it with my vice grips and got it out.
Looking back inside the contacts to where the screw would have come out from. Basically the power arced from the near tab across the other contact and AGAIN through the screw. Path of least resistance to the main wire. The screw was melted into place.
In addition to arcing through the contact, you can see it arced completely along the length of the contacts, shortest path being the gap between the 2 plates at the housing, where it melted. All the carbon buildup is on the base of the tabs, away from where the shuttle was in full contact. On the backside of the tab that arced to the screw was also black, it was burned on both sides.
The housing split open so you can see the amount of damage to the spot where the screw sits through the contacts.
A mosfet would have 100% prevented this. Had this gun continued being used when this damage initially occured, it's possible the contacts would've melted through the nylon completely and merged the 2 contacts together creating a runaway. Worst case was that the gearbox shell itself could've electrified and arced, causing more damage to the shell itself or possibly injury, as your finger is on a big metal trigger very close to this action.