CaptainSwoop Posted April 2, 2014 Posted April 2, 2014 One of my M4s will only select auto,, Safety works but it is auto in both of the other positions. WHen I stripped the gearbox shortly after I got it to check it out and refurb (it is an ex rental gun) everything looked ok. I am wondering if the cut off has some wear on it that isn't obvious?
Supporters Samurai Posted April 2, 2014 Supporters Posted April 2, 2014 The wear on the cutoff is really hard to see. You can screw the gearbox together without the spring and the cylinder and turn the gears with your finger. You'll see how much the cutoff moves. Then you can pull the trigger with your third hand and see if the cutoff can push the contact lever off from the trigger. But the wear of the cutoff results more and more autofire in semi mode. So it's not like having a fine single fire and in the next moment full auto only. It's more like a few short bursts at first and it's getting worse gradually. Check the selector plate and it's spring too.
CaptainSwoop Posted April 2, 2014 Author Posted April 2, 2014 Thanks for that. New cut off it is then.
straffham Posted April 15, 2014 Posted April 15, 2014 Had a similar problem after servicing my M16. Turns out the small spring between the fire selector plate and the cut off lever had dislodged so wasn't lifting the cut off. Works fine now its been replaced. Monty 1
CaptainSwoop Posted April 16, 2014 Author Posted April 16, 2014 Could be worth checking the spring. It is there but could have lost it's 'springyness'
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