Weird Semi Problem

Fireboy · October 27th, 2007, 22:06

I searched the forums and couldn't find a similar problem as mine so here it goes:

Shoots full auto fine. Take one shot semi...gun stops working. Trigger pulls fine but nothing happens. Even when I switch it back to full auto, the gun no longer fires. I did some upgrades to it including a Systema Low Resistance trigger switch so I'm a little confused?

BTW - It's a Version 2 Mechbox on a G&P M4.

Any help is appreciated.

mcguyver · October 27th, 2007, 22:59

Broken switch stop block. Open your mechbox and look at the square post behind the trigger contacts and see if it's broken away for the mechbox shell.

lupo · October 27th, 2007, 23:31

Could also be the little disc attached to the selector. I had a customers that was originally a tight selector switch and over time the disc spun on the selector and wasent moving the selector plate into semi auto properly. I would have the mechbox out of the gun and it would fire in semi and full fine but in the body it wouldnt fire semi , only full.

Greylocks · October 28th, 2007, 08:57

What other modifications were made? Details may be important.

Fireboy · October 28th, 2007, 11:23

Mr. Mac has it I believe. The little post behind the trigger switch appears to have the upper portion sheared off in comparison to a second V2 mechbox I have.

CDN_Stalker · October 28th, 2007, 12:13

I've fixed a couple of mechboxes that had the little post break off. Literally I drilled a small hole, used a #4-40 tap to thread the hole, then screwed in a small but long set screw (with LocTite). Worked every time.

mcguyver · October 28th, 2007, 12:17

Yay, Me!!

Crappy for you, as the best way to fix it that I've found is to grind the remainder of that post flush with the shell, drill a hole, tap it, insert a screw with Loc-tite and grind the screw flush on the outside of the mechbox shell and cut it on the inside to the correct height (so that it stops the switch contact yet clears the sector gear teeth).

Leave the Loctite to cure for at least 24 hours. You can use permanent red Loc-tite, as this never needs to be removed again. It'll take a bit of work, but be stronger than the original by far. A Dremel is best for grinding and cutting, and you'll have to totally clean and re-lube the mechbox after to eliminate the metal cuttings.

Edit: Damn you Stalker and my two-fingered typing!!!

Fireboy · October 28th, 2007, 13:26

Or...........I could buy a new mechbox......LOL

CDN_Stalker · October 28th, 2007, 13:29

Quote:

Originally Posted by mcguyver

Edit: Damn you Stalker and my two-fingered typing!!!

And yes Fireboy, you can get a $40 King Arms reinforced mechbox from airsoftparts.com if you want to go that path.

Fireboy · October 29th, 2007, 01:38

Nah.....ehobby or any of the other HK stores.

CDN_Stalker · October 29th, 2007, 01:51

Why buy out of country when you can get a $40 reinforced mechbox in Canadian funds from within Toronto?

swatt13 · October 29th, 2007, 02:11

the repair mcguyver is talking about isnt as hard as it sounds, drill hole, insert screw, grind flush, and voila! done. itd take a half hour at tops. all you need is a machine screw, dab of loctite, and a drill. ive done it to my systeam mechbox.

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October 27th, 2007, 22:06	#1
Fireboy Trader rating Join Date: Dec 2006 Location: Alberta, Earth	Weird Semi Problem I searched the forums and couldn't find a similar problem as mine so here it goes: Shoots full auto fine. Take one shot semi...gun stops working. Trigger pulls fine but nothing happens. Even when I switch it back to full auto, the gun no longer fires. I did some upgrades to it including a Systema Low Resistance trigger switch so I'm a little confused? BTW - It's a Version 2 Mechbox on a G&P M4. Any help is appreciated. Last edited by Fireboy; October 27th, 2007 at 22:55..

October 27th, 2007, 22:59	#2
mcguyver Trader rating Join Date: Aug 2005 Location: Northern Alberta	Broken switch stop block. Open your mechbox and look at the square post behind the trigger contacts and see if it's broken away for the mechbox shell. __________________ Age verifier Northern Alberta Democracy is two wolves and a sheep discussing what's for dinner. Freedom is the wolves limping away while the sheep reloads. Never confuse freedom with democracy.

October 28th, 2007, 12:13	#6
CDN_Stalker Official ASC Bladesmith Trader rating Join Date: Jul 2003 Location: Ottawa, Ont.	I've fixed a couple of mechboxes that had the little post break off. Literally I drilled a small hole, used a #4-40 tap to thread the hole, then screwed in a small but long set screw (with LocTite). Worked every time. __________________ STKR Knives http://www.facebook.com/#!/pages/STK...17036668380871

October 27th, 2007, 23:31	#3
lupo Trader rating Join Date: Dec 2001 Location: vancouver	Could also be the little disc attached to the selector. I had a customers that was originally a tight selector switch and over time the disc spun on the selector and wasent moving the selector plate into semi auto properly. I would have the mechbox out of the gun and it would fire in semi and full fine but in the body it wouldnt fire semi , only full.

October 28th, 2007, 08:57	#4
Greylocks Trader rating Join Date: Dec 2001 Location: Gatineau, Quebec (Near Ottawa)	What other modifications were made? Details may be important.

October 28th, 2007, 11:23	#5
Fireboy Trader rating Join Date: Dec 2006 Location: Alberta, Earth	Mr. Mac has it I believe. The little post behind the trigger switch appears to have the upper portion sheared off in comparison to a second V2 mechbox I have.

October 28th, 2007, 12:17	#7
mcguyver Trader rating Join Date: Aug 2005 Location: Northern Alberta	Yay, Me!! Crappy for you, as the best way to fix it that I've found is to grind the remainder of that post flush with the shell, drill a hole, tap it, insert a screw with Loc-tite and grind the screw flush on the outside of the mechbox shell and cut it on the inside to the correct height (so that it stops the switch contact yet clears the sector gear teeth). Leave the Loctite to cure for at least 24 hours. You can use permanent red Loc-tite, as this never needs to be removed again. It'll take a bit of work, but be stronger than the original by far. A Dremel is best for grinding and cutting, and you'll have to totally clean and re-lube the mechbox after to eliminate the metal cuttings. Edit: Damn you Stalker and my two-fingered typing!!! __________________ Age verifier Northern Alberta Democracy is two wolves and a sheep discussing what's for dinner. Freedom is the wolves limping away while the sheep reloads. Never confuse freedom with democracy.

October 28th, 2007, 13:26	#8
Fireboy Trader rating Join Date: Dec 2006 Location: Alberta, Earth	Or...........I could buy a new mechbox......LOL

October 29th, 2007, 01:38	#10
Fireboy Trader rating Join Date: Dec 2006 Location: Alberta, Earth	Nah.....ehobby or any of the other HK stores.

October 29th, 2007, 01:51	#11
CDN_Stalker Official ASC Bladesmith Trader rating Join Date: Jul 2003 Location: Ottawa, Ont.	Why buy out of country when you can get a $40 reinforced mechbox in Canadian funds from within Toronto? __________________ STKR Knives http://www.facebook.com/#!/pages/STK...17036668380871

Weird Semi Problem

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