Firing 2 bb's at once in semi?

[simon]

My M4 has been fine for the past 3 years but today it seem to be firing 2 bb's at once in semi. Every thing looks fine and the metal hop dosent seem to have any issues. Any one had this problem and know what's wrong? And no it dosent have a round burst fitted.

[Bachelarius]

Re: Firing 2 bb's at once in semi?

Is it feeding two bbs and firing them both with one blast or is it 1 semi trigger pull = 2 basts of air.

If it's the first one, then something odd is going on with the hop rubber. Does it still happen with a higher hop setting? If so, new rubber time. Also, check over the air nozzle on the gearbox, make sure it's not got bits missing out of it or something, haha.

If it's the latter, its over-rotation. What battery are you using and what fps are you firing at? May well be a worn out Tappet plate spring or mainspring. If it's got a low fps, you need a new mainspring, else try a new tappet spring, which will help mitigate the over-rotation. Worst comes to worst, an active braking mosfet will remove the problem as well, but that's a bit of a 'throwing money at a problem' solution and isn't necessary, as your gun was working fine without it.

[simon]

Re: Firing 2 bb's at once in semi?

It's the first one 'feeding two bbs and firing them both with one blast', it's happening with no hop and full hop so I will swap over my hop rubber and see what happens. The nozzle looks fine.

[Bachelarius]

Re: Firing 2 bb's at once in semi?

It may be worth manually feeding bbs into the feedtube and firing the gun upside down, seeing if it still does it or take the hop and barrel assembly out and directly feeding a mag into it, mimicking the air nozzle action manually.

[simon]

Re: Firing 2 bb's at once in semi?

Hop seems fine but the loading nozzle seems to go back twice on one pull of the trigger which will load 2 bb's. Will have to open the gear box and have a look.

[simon]

Re: Firing 2 bb's at once in semi?

Took the gear box apart, nothing seemed wrong. Checked the nozzle and guide, all fine. Put it all back together and now fires one shot with one pull of the trigger. Must just be one of those things! Thanks for your input Bachelarius.

[Bachelarius]

Re: Firing 2 bb's at once in semi?

No worries, must have been catching on something.. no clue what though, watch it carefully for the next month or so. Happy hunting!