TRIGGER HAPPY thanks for the great presentation and kicking me in the butt to help go forward with a story about installing the new trigger bar, which gives a significant reduction of take up travel of the trigger.
There are many disclaimers I want to put out there before I get started.
This is what I did to MY gun. The following is meant as informational and not given as advice. How i found out how this gun functioned is after replacing the trigger bar I still felt a “glich” in the trigger pull. I pulled my hair out at first. Then came back to MCARBO FORUM and saw a new thread by triggerhappy and started to think.
i saw triggerhappy’s diagrams and the light came ON. I started to look at partially assembled receiver and pulled he trigger with no safety in the gun(I KNEW THE GUN WAS SAFE BECAUSE WAS NO BOLT IN THE GUN) but that was a mistake because the hammer is now inside the grip !!! so I had to disassemble the grip again. this was good because now when i reassemble I will place bolt in before testing anything EVER AGAIN !!
So the gun is cock and bolt in place, I pull the trigger and then hammer drops and then I pull back and re-cock the hammer and let the bolt close on the barrel. Now I wanted to know "how does the safety work. I placed the safety pin in place with one e-ring and no detent ball but the safety still moves back and forth and can be placed in any position between safe and fire. At that point in time I realized that the bar moves up or down because of pressure against the surfaces of the pin and if i just lightly pulled on the trigger and move the safety pin back and forth I could “FEEL” all the rough places on the matting surfaces.
When the bar would engage the sear and also watch how the bar would push back and forth on the safety pin. I started to think when does happen I thought back to triggerhappy;s diagram and figured there is ANOTHER surface involved. Surface A (in the picture below) that contacts the safety pin that moves the TB up and down engaging the sear or clearing the sear.
if engaged with the sear, in fire position, then pulling the trigger makes the bar go forward pushing the sear forward off the bearing surface of the hammer. The smoother these surfaces are the easier it will be to make the sear go forward the smoother reducing the pressure it takes to move the sear.
I now have the surfaces so smooth I can stop the sear right before it passes from below the hammer and the hammer is released.Letting off of the trigger sets the sear in a “hair trigger condition”. At that point the ONLY the rear edge of the sear bearing surface is in contact with the hammer. making the very narrow piece of metal real smooth helps ALOT.!!!
Tools that i have to do the polishing described below. Not all sand paper is shown. depending on how much materal I want to remove I either start with flat/curved/round files or a grinding tip for interior surfaces or just course sand paper, then follow with 120/400/800/1000/1500/2000 grit paper( i wrap these different grits around a flat file to control removal of material) and always finish with Dremel and Flitz.
On large surface areas that carry high pressure loads (like the interface between the bolt and bolt tube, especially the front of tube right behind chamber) I like to use a good quality Molybdenum grease. I can also use this in PCP guns.
I use a 7x optic to check for progress go slow and adjust as required.
EXAMPLE of polishing
Notice the very small shiny surface at leading edge of bottom of bolt. I used a flat file to start radius. On some curved surfaces( like the curved surface on the rear of the bolt that starts the cocking of the hammer (after firing) I start with a light use of an appropriate grinding stone on a Dremel to create either radius or bevel to reduce impact vibration. Then went through sand paper wrapped around the flat file going from 120grit/400grit/800 grit/1000grit/1500grit finishing with 2000 grit then the Dremel tool and Flitz
Hammer bolt interface slightly radiused just enough to reduce drag (no dimensional change) just smoothed enough to reduce impact vibrations.
bottom of bolt where hammer rides when charging after firing. On the rear of the flat surface (inside of the curved face) I eased a slight radius where the bolt and hammer engage after firing to start cocking motion. I also put a slight radiuse on the appropriate face of the hammer. this all helps to reduce vibrations. It might even reduce time to cycle.
bolt hammer alignment in charging tube
I have cycled the gun and have noticed No change in function other than that of smoother action.
With all that in mind if someone does not know what they are doing and create any unsafe conditions while working on their on gun following the illustrations and concepts I am putting out here, accept no liability.
The pictures, for illustration purposes are here to show approximate orientation of working parts in different configuration at different times of operation.
cocked in safe mode
cocked in safe mode with trigger pulled
safety in fire mode gun ready to fire.
After gun fired
Trigger bar (with safety removed) with safety on. for illustration of movement of trigger bar not engaged with sear
Trigger bar (with safety removed) with safety in fire position (note the small gap below the trigger bar and safety pilot hole).
A side view of how parts stack when assembled (from rear)
Illustration of relationship between safety pin and trigger bar and hammer pin bushing in safe position pushing trigger bar down disengaging sear. The polished surface in these pictures does not show very well but all surfaces are mirror finished. there is a lot of pressure between the A surface of the trigger bar and the surfaces that rides on on the safety pin.
actual picture of above condition
position of trigger bar when in safe mode when trigger is pulled.
illustra!tion of relationship between safety pin and trigger bar and hammer pin bushing in fire position.
actual picture of safety in fire mode [Uploading: over view with safety in fire mode.
trigger bar position in fire mode when trigger is pulled
In all pictures above note the relative position of trigger bar and the hammer pin bushing. the trigger bar is puched against the hammer pin bushing when going into fire mode and when the trigger is pulled it drags over the bushing along surface B in the following diagram. Note the shiny edge of that surface i smoothed the square edge giving it a larger radius reducing drag.
I also cleaned up the edge of the hammer pin bushing reducing drag see illustrations above.
Safety pin polishing note, remove O-ring before polishing see illustrations above.
please see trigger bar illustration above for trigger bar/safety bearing surface A that is the surface that contacts the safety pin.
surface A polished with attention to edges.
A better picture showing polished safety pin surfaces. Look closely at step down surface on safety pin. that is me taking the picture. DO you think it is polished ?
Please see illustration above for trigger bar surface C. Consider all the edge surfaces of the trigger bar that are inside the notch as bearing surfaces.that is the contact area that engages the sear.
polish it and pay attention to making the outside radius of notch at C smooth !
Please see illustration above. The edge of surface B rides along the outer face of the hammer pin bushing and is pushed towards it as the safety pin moves from safe to fire. That caused the “glitch” i was feeling as i started to pull the trigger and again as I let off the trigger. I put a very narrow bevel on the bushing to make that transision seamless.
Below is picture of hammer profile note polished sides. Pay particular attention to hammer hook profile
Next 2 pictures are sear surfaces ,
Polish the sear trigger interface, if you look real close at the flat surface where bar rides against sear you can see the deeper mill marks that are still left on sear. just lapping the corner of sear where it rides up and away from the bar at firing makes that momentary contact effortless. Look at edge of hammer pin bushing, see bevel i created to smooth out the interface between it and trigger bar.
Sear hammer interface. Notice the very thin shiny edge of rear of sear hammer interface. Again, this is the last surface that touches the hammer hook while firing
Sear hammer interface
Edge of hammer bearing surface. Note the deeper mill marks are not the issue the higher surfaces are the issue. I drive this point home again…Again leaving the deeper mill marks there give an area where the lubrication (super lube w/ TPFE) has a chance to stay there and lubricate
Polished side of trigger bar. I put a very small bevel on the leading edge of side B (see illustration above) to ease the contact between trigger bar and hammer pin bushing
the end results trigger pull in safe mode SILKY SMOOTH
trigger pull when firing SILKY SMOOTH
All surfaces that were polished were soaked heavily cleaned with CLP,.let to soak for 5 miutes before whipping dry. All bearing surfaces, excluding Bolt and barrel hinge pin, were lubricated with SUPER LUBE before reassembly. Bolt and barrel hinge pin were treated with 60% high pressure, high heat, moly paste.
Sorry this got so drawn out but wanted to make sure it was explained.
HAPPYTRIGGER time !
Now I am going to post it then read it and edit. Please forgive my grammatical errors !!