Part 2. King Arms M1A1 Thompson (Level 4 Redwolf Airsoft upgrade)

I have taken the gearbox apart to trouble shoot it 4 times now, I was able to get the semi automatic for a short period of time but after a several test shots it goes back to being problematic, at times not shooting anything at all and I am afraid the problem is far worse than just the gun not being able to shoot semi automatic.
- in semi automatic mode, it slips letting off more than one shot (each trigger pull yield different results / quantity of shots)
- motor gear seems to be clicking/slipping and or grinding against the gearbox gear, gearbox gear with less than 100 shots already shows wear.
- air nozzle head does not retract fully, blocking the chamber causing constant misfeeding

My conclusion: The wear on the gear shows this gun has a serious problem and the problem with semi automatic mode shows something is seriously faulty in the gun. The air nozzle does not retract causing blocking of chamber and misfeeding of bb's making this gun inoperable even if the above two issues were in working order.

Category:

Music

Tags:

• redwolf airsoft
• king arms thompson military
• prometheus tightbore barrel
• systema gears

[g3tr00t3d]

it's normal for the nozzle to not return either completely in or out. the problem you are having is compression loss. it's usually leakage between the nozzle and hopup bucking. while you had the gearbox open, have you tested cylinder piston compression? your gears look dry, so i'm going to assume you never lubed the piston o-ring. it needs to be lubed to seal air properly.

[julitoculito]

@g3tr00t3d I lubed the piston head with silocone spray, gears were greased, I did not check for compression, I will take it apart and see. But my main concern was with how the bottom gear was starting to get chew marks. and why the misfeeding of the bb? I can understand the compression being the reason why the bb has such terrible trajectory but something else is going on here. also keep in mind this was put together professionally by redwolf airsoft and arrived brand new to me.

[222yankees222]

hey i have the same gun i had the 1000 rd drum the spring broke the first day so i bought another came yesterday and the same thing happened do you think is because it is a high cap mag and it works the spring to much at once or just bad luck? ive been through about 50-60 dollars worth of clips so far... do you think it would be a good investment to get a medium cap 110 rd king arms stick mag 50 dollars for a 5 pack?

[julitoculito]

@222yankees222 I very much prefer stick mags over drums. They just look better.maybe you are overwinding the drum mag? careful how you wind the mag and the mag spring tension, and also winding it the wrong way. I have 5 stick mags (the 380 round ones) and zero problems

[samsam828]

hey man i have the same gun except for the drum clip version. it works great except my some times (rare) it gos full auto on semi just like your but not nearly as often should i be worried?

[julitoculito]

@samsam828 I wouldn't be worried, my issue is due to the upgraded spacers on the gearbox, installed at redwolf airsoft, they interfere with the switch, try looking at a thompson disassembly youtube guide, it's rather easy to get down to the switches, take a look at them make sure they're flush, put the gun back together and see if it changed anything. otherwise it shouldn't hurt the gun, just an inconvenience.

[MrMovienator]

How long did you have it till this happened?

[PhotoshopTimes]

Dude....Your cylinder is in backwards. You see how the hole on the cylinder is towards the cylinder head? Thats where all of you air is going causing the *compression issue*. Turn that around and reshim the gun.

[g3tr00t3d]

@g3tr00t3d kalashnikob is correct about the grinding. attach the motor and the bevel gear. adjust the motor height so the motor's pinion gear has full contact with the bevel. use shims on the bottom of bevel to level it out. next remove the motor and screw the gearbox cover on. push the bevel axle from below and check how far it moves up the gearbox. if it has no movement, it is too tight and need to reduce the shims. too much play, add shims on top. there needs to be a little play.

[kalashnikob1]

Reshim the gears, the bevel gear is too low which is causing the pinion to grind it like that. Watch my video on shimming