Trigger trolley compatability
 

So my King Arms M4a1 has many sharp edges internally that have cut into my wires. I purchased a low resistance, silver coated wire kit that is already soldered. My problem is the new trigger trolley has two contact pins that my original trolley does not. Are these parts compatible? My guess is that they are a safety feature to break the circuit when the gun is put in safe. However I figured I'd ask you guys to be safe. Thanks in advance...

For that type of switch you need either a metal selector plate or one with a metal contact plate to bridge the gap between those prongs.

My selector plate has the contact plate. Would this be a downgrade??? another contact point seems like anther place to fail. Thanks for the help Wrath144. Ive heard king Arms internals are pretty good and I don't wanna replace parts with lesser quality.

If you're worried about that then take the switch apart and use the metal parts from the KA contacts.

hmmmmmmmm good point.

It is not really a downgrade. It is a further safety by separating those contacts when you put it in "safe". I often will solder the two contacts together with a tiny piece of wire if my selector plate does not have the metal contact piece.

I would not reuse the contacts from the KA original trigger mechanism. I have found they get really fouled with carbon quite easily.

First; what we usually refer as the "trolley" is the part that is pushed by the trigger and closes the circuit. What you have in hands is the whole trigger switch assembly, or trigger contacts assembly.

Second; these pins are closed, as other mentioned, by the metal plate on the selector plate. The safety option others mentioned is made by connecting, or disconnecting when in safe, the circuit.

I'm bridging those two prongs together because I hate having multiple connection points, thus multiple points of resistance. If you don't have a mosfet, the circuit should never need that safety, and if you have a mosfet that fails (closed), that safety is useless. [I guess if you regularly forget your batteries plugged, it may be good to use that safety.] Edit: Forget the last part, see below.

Nope. The trigger is already open, so even with batteries plugged nothing happens.

Right. Thanks for the precision.