Topic: GSG 522SD Firing multiple rounds (Read 2265 times)

Kilibreaux · « **Reply #15 on:** February 08, 2011, 06:29:09 PM »

Since my last post I have finally identified the real reason for GSG multiple fires. The sear housing spring is relatively weak and fails to consistently snap the sear housing up with sufficient force to engage the hammer notch. Additionally, the sear/hammer engagement angle is not ideal for inducing the sear and hammer notch to slide INTO engagement with minimal pressure.
The simplest solution is to take a "click pen" spring and shorten it to just longer than the space between the sear housing and trigger housing. Insert the stock spring into it to create a "double coil" which will double the force exerted on the sear housing when the hammer impacts the disconnector and causes the sear housing to snap upward. Even without reshaping the sear and hammer notch, doubling sear housing spring pressure should solve the multiple fire problem.

mastercamper · « **Reply #16 on:** March 10, 2011, 11:49:36 PM »

Quote from: Kilibreaux on October 18, 2010, 12:44:41 AM

Well...here's the answer everyone has been waiting for:
The "sear housing" spring tends to be relatively weak. This is the small spring located in the front portion of the trigger housing. At the same time the sear to hammer engagement is not optimized...by this I mean the hammer notch is bisected by a slot that leaves relatively small engagement surfaces on either side. To add to the potential problem, the hammer notch is not precision cut and angled, and thus has rounded edges rather than sharp which simply add more to the potential for partial sear engagement. The sear is also installed "as cast" without benefit of any truing of engagement surface, or honing to produce an engagement angle that cause the hammer notch and sear to pull into engagement with applied spring pressure.
During the firing cycle the trigger is pulled and this retracts a safety arm from beneath the sear housing, thus allowing the housing to rotate downward. The hammer comes back and smacks the disconnector and this releases the sear housing to snap upward under sear housing spring force thus engaging the hammer notch. Due to the additive impact of all mentioned variables, some GSG's may work fine, others will exhibit multiple firing every so often due to partial sear engagement that is easily dislodged during the bolt's cycle.
For me the cure was to add a second spring outside (around) the factory spring...basically I shortened a click pen spring to slightly longer than the space between sear housing and trigger housing opening and slide the two springs together, then inserted. I reshaped and honed the hammer notch and the sear for a more "positive", higher surface area engagement with an angle that causes the two surfaces to slide "into" engagement with even modest spring pressure. Took the modified GSG out and over 200 shots had zero multiple fires. Before the mod I would usually get a multiple every 20 shots on average with the frequency increasing as the GSG warmed up.

hey if you could post a video on youtube explaining what you did that would be much appreciated thanks.