Trigger creepiness, chapter two and some data

Trigger creepiness, chapter two and some data

Joined: March 1st, 2002, 12:22 am

November 2nd, 2011, 4:17 am #1


Ok, I admit to having the living sh*t annoyed out of me by this low dollar, never-meant-to-be-a-match-trigger POS on the 760

And I'll cop to be more than a little obsessed by it.  

Tonight's misadventures got it much more crisp.

 The Data:

ID of the pump tube: ~.625

OD of the hammer ~.610

OD of the "base" of the spring guide" ~ .605

So the design has some slop in it, probably to facilitate manufactureing and assembly. Just taking the hammer, and moving it thru the slop with my finger tip doenst account for the percieved movement I saw over the week end. The fit of the spring guide in the pump tube is considerably looser than than the hammer in same.

I wrapped one turn of vinyl electrical tape around the base of the spring guide to bring it closer to the ID of the punmptube, and reassembled. It helped, but its still <read this in yer best Bela Ligosi> very creepy

Pulled it apart again, and looked it all over. The hammer showed the obvious point of contact with the sear, and diagnostics over the weekend showed where the sear was worn from sear contact. This made it very clear that the "shelf" the sear locked on to is slightly less than vertical, having a slight lean toward the rear of the gun.

So this means that the very small point of contact on the sear is d r a g g i n g across the face of the "shelf", and the hammer does deflect a minute amount, but not the inches Sunday;s work seemed to indicate. The combination of the two symptons generate the creep.

I forget if Rob or Andy said to reduce the contact of the sear with the face of the hammer. Didnt register till this evening, but that has been promising. I have been trying to see where I could add some set screws to reduce take up and over travel, but the design mostly precludes that. Staring at it some more, I hit on adding a 3/32 or so biit of wood on the clamshell gbehind tha safety to do what the setscrew would have. it stops the sear from engaging the hammer further up on the "shelf"

Tests with that bit in place make the trigger much less creepy and almost crisp. need to figure a way to get a set screw in that spot for some precise adjustments.

And..... I do believe it possible to add a second lever in the trigger chain (ala the B800 pistol) and get some better feel and function.

 


dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic
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Joined: April 28th, 2010, 12:23 am

November 2nd, 2011, 4:50 am #2

were not doing a buildoff for a while. its driven us both insane.(my family said so)all that aside, i see where youre goin. reducing mating surface will help, but perhaps not as much as having the hammer travel "true".i got to the point where my travel was so much it didnt clear my trigger gaurd , and no3w i found the solution.im hoping u find the shortest(least time consuming) solution. bc I havent.mine involved the bullpup linkage
Last edited by robnewyork on November 2nd, 2011, 1:36 pm, edited 1 time in total.
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Joined: February 9th, 2006, 10:35 pm

November 2nd, 2011, 11:34 am #3

Ok, I admit to having the living sh*t annoyed out of me by this low dollar, never-meant-to-be-a-match-trigger POS on the 760

And I'll cop to be more than a little obsessed by it.  

Tonight's misadventures got it much more crisp.

 The Data:

ID of the pump tube: ~.625

OD of the hammer ~.610

OD of the "base" of the spring guide" ~ .605

So the design has some slop in it, probably to facilitate manufactureing and assembly. Just taking the hammer, and moving it thru the slop with my finger tip doenst account for the percieved movement I saw over the week end. The fit of the spring guide in the pump tube is considerably looser than than the hammer in same.

I wrapped one turn of vinyl electrical tape around the base of the spring guide to bring it closer to the ID of the punmptube, and reassembled. It helped, but its still <read this in yer best Bela Ligosi> very creepy

Pulled it apart again, and looked it all over. The hammer showed the obvious point of contact with the sear, and diagnostics over the weekend showed where the sear was worn from sear contact. This made it very clear that the "shelf" the sear locked on to is slightly less than vertical, having a slight lean toward the rear of the gun.

So this means that the very small point of contact on the sear is d r a g g i n g across the face of the "shelf", and the hammer does deflect a minute amount, but not the inches Sunday;s work seemed to indicate. The combination of the two symptons generate the creep.

I forget if Rob or Andy said to reduce the contact of the sear with the face of the hammer. Didnt register till this evening, but that has been promising. I have been trying to see where I could add some set screws to reduce take up and over travel, but the design mostly precludes that. Staring at it some more, I hit on adding a 3/32 or so biit of wood on the clamshell gbehind tha safety to do what the setscrew would have. it stops the sear from engaging the hammer further up on the "shelf"

Tests with that bit in place make the trigger much less creepy and almost crisp. need to figure a way to get a set screw in that spot for some precise adjustments.

And..... I do believe it possible to add a second lever in the trigger chain (ala the B800 pistol) and get some better feel and function.

 


dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic
My SOP for 760 triggers for a few years now has been to shorten the pull. If done right it makes for a decent yet safe trigger.
Sorry, but that's all the info I can share right now. You'll see the rest later this month. Mmmuuuuhahahaha!!!!! (creepy laugh!)

I plink, therefore I am.
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Joined: March 1st, 2002, 12:22 am

November 2nd, 2011, 2:29 pm #4


reducing the amount of sear engangement from the get go.

Yes the hammer still moves, but its small. the creep comes frmo the sear grabbing hold soooo far up on the hammer, it just take a long time to move it clear. But while this is going on, your finger is on the trigger feeling all this as it pulls free of the hammer.

Ah, now doing this safely.... Last night had it _very_ crisp, but slightly heavy (thats Ok by me). and very unsafe. rapping the side fot he gun would set it off. So there is the trade off.


dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic
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Joined: February 9th, 2006, 10:35 pm

November 3rd, 2011, 12:36 pm #5

I can slap the receiver and bang the butt on the floor and no misfires. trigger isn't match grade, but a WHOLE lot better than stock.

I plink, therefore I am.
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