The Allen head screw in the trigger is a trigger over-travel adjustment screw.
This screw is used to adjust how far the trigger travels AFTER the hammer is released.
Be VERY careful with this. Usually these are set correctly at the factory. If you attempt to adjust it farther in you can easily cause the gun to fail to fire at all. With the trigger stop set too far in, the hammer won't release smoothly, or may not release at all.
Many people who use 1911's as an actual defense gun will either back the screw out more and use more Loctite to be SURE it won't move, or they simply remove the screw entirely to prevent any chance of the gun being deactivated by a screw that moves.
The trigger over-travel adjustment screw really belongs on a true Target Match gun where a failure won't get you killed.
A Series 80 1911 has several extra and/or different parts.
In the frame are two levers, one on the sear pin, the other on the hammer pin.
When the trigger is pulled, these interlocking levers are pushed upward to deactivate the firing pin lock.
In the slide is a plunger and spring firing pin lock, and a firing pin and extractor that are different.
When the trigger is pulled the levers in the frame push the firing pin lock up, unlocking the firing pin so the gun will fire.
If you disassemble the frame, it's CRITICAL that you get the levers back in place properly interlocked. If you fail to do so, when the trigger is pulled the firing pin will NOT be unlocked, the gun will not fire, and the firing pin and firing pin lock will be damaged.
This is a dangerous situation because unless you properly check the assembly, you have no way of knowing the firing pin will not unlock properly.
To test the Series 80 firing pin lock system, you can do the following.
With the slide off and the hammer DOWN, pull the trigger. The firing pin lock lever beside the hammer in the frame should be pushed up out of the slide.
Another way is to drop a pencil down the UNLOADED barrel, point the gun upward and pull the trigger. If the system is installed correctly, the pencil will be shot out the barrel with some force.
This screw is used to adjust how far the trigger travels AFTER the hammer is released.
Be VERY careful with this. Usually these are set correctly at the factory. If you attempt to adjust it farther in you can easily cause the gun to fail to fire at all. With the trigger stop set too far in, the hammer won't release smoothly, or may not release at all.
Many people who use 1911's as an actual defense gun will either back the screw out more and use more Loctite to be SURE it won't move, or they simply remove the screw entirely to prevent any chance of the gun being deactivated by a screw that moves.
The trigger over-travel adjustment screw really belongs on a true Target Match gun where a failure won't get you killed.
A Series 80 1911 has several extra and/or different parts.
In the frame are two levers, one on the sear pin, the other on the hammer pin.
When the trigger is pulled, these interlocking levers are pushed upward to deactivate the firing pin lock.
In the slide is a plunger and spring firing pin lock, and a firing pin and extractor that are different.
When the trigger is pulled the levers in the frame push the firing pin lock up, unlocking the firing pin so the gun will fire.
If you disassemble the frame, it's CRITICAL that you get the levers back in place properly interlocked. If you fail to do so, when the trigger is pulled the firing pin will NOT be unlocked, the gun will not fire, and the firing pin and firing pin lock will be damaged.
This is a dangerous situation because unless you properly check the assembly, you have no way of knowing the firing pin will not unlock properly.
To test the Series 80 firing pin lock system, you can do the following.
With the slide off and the hammer DOWN, pull the trigger. The firing pin lock lever beside the hammer in the frame should be pushed up out of the slide.
Another way is to drop a pencil down the UNLOADED barrel, point the gun upward and pull the trigger. If the system is installed correctly, the pencil will be shot out the barrel with some force.