Javelin M4 issues

[Shadowsta13]

At recent game while using a friend's Javelin M4 I noticed that it was malfunctioning, specially firing full-auto in semi-auto. Positively there is no problem with the safety. The rifle in question is about 8 months old. It also has problem with it's fake bolt getting stuck when the charging handle is pulled back. Anyone understand what's wrong with it internally?

[CADPAT]

Is he using a Li-po, and what is the exact Javelin M4 he has?

[Payback]

Could be the cutoff lever worn down. Not resetting the trigger on the semi auto setting. Could be the trigger contacts have gotten corroded and getting an arc. Could be the selector plate/cut off lever spring worn down and needing to be stretched a bit.

And for the fake bolt getting stuck, just pop off the upper and take a look. It could just be some bent tabs on it, might just need to be straightened.

[Shadowsta13]

Could be the cutoff lever worn down. Not resetting the trigger on the semi auto setting. Could be the trigger contacts have gotten corroded and getting an arc. Could be the selector plate/cut off lever spring worn down and needing to be stretched a bit.

I was thinking it might be the trigger contacts, I'll try to take a look at it as well as the cut off lever and such.