Hello, guys! The weapon with the semi-auto seizure is a VFC SCAR-L CQC. It shoots at ~415 fps (0.20 g). The battery is a LiFePO4 9.9v 15C 1000 mAh. The problem occurs whenever I pull the trigger repeatedly and rapidly (even if on complete yet rapid pulls). Additional info: The gun, which used to drain batteries right on the first day of gaming, remained "down for maintenance" for some time and then I found it was a loose motor connector. When I restored the battery, which I thought to be the faulty part as it had one completely-drained cell, I noticed my AEG was a bit slow trigger response-wise, even with other LiFes and 7.4v LiPos. The weird thing is that in my last game, some days ago, it wasn't locking that easy anymore on rapid semi-auto. The RoF has always been slow, but I THINK that's normal for its stock motor and that battery (is that?). Interesting weather notes: a) some games ago, a friend noticed its pistol grip was somewhat hot after we checked its semi-auto for some time (he was wearing Mechanix Originals); b) the day the AEG worked "properly" (as mentioned in the previous bold text ^) was colder than usually, yet being hot for some (~20ºC / ~68ºF) - (video right below). [TLDR] * YouTube link with the AEG firing on semi-auto and full-auto - TURN ON ANNOTATIONS * [ame]https://www.youtube.com/watch?v=jPqyurhK7LE[/ame] Of course I want to avoid opening the mechbox for no reason and possibly messing something up, thus I'm asking for help; any insight for troubleshooting is welcome. Possible reasons for the issue: 1. stock wiring set and regular mini-Tamiya plugs. Should 16 awg properly fit in its gearbox? Else, is 18 awg ok? If changing plugs, I'll opt for Deans, don't you worry haha; 2. insufficient power. Not sure if the "half-cycle" shown in the video is caused by that. But if the LiFe can't handle it properly, what could (with NO harm)?! :'( 3. auto-shimming gears. Makes sense? If so, in order to shim my mechbox, would I need to change its gears or just the shimming set? Because gears are expensive here in Brazil (as I believe you wouldn't recommend random gears, but good ones); 4. faulty/weak motor. I'll just throw in ZCI 22 TPA in it if that's A MUST for this moment, as the currency is terrible now; 5. motor height adjustment. Not sure if the whining sound (video above ^) is due either to item 4 or 5, or if that's normal for VFC; 6. faulty/weary piston. Does that make sense? Thank you so much; I'm sorry for the long post.