logo by smgunner

Dean's HiPac 2240

Tactical Trijicon ACOG TA01 Style 4x32 Cross Sight Rifle Scope + Kill Flash
TROBB Solid Aluminium Dovetail Power Block with Gmac hollow probe and G-mac Bolt
Gmac Brass Power Adjuster Spring And Guide/Drilled Out Standard Valve For more air space
Hammer Mods//Gmac 30% Lighter valve Spring/Gmac Brass Safety Catch//Transfer port drilled out
Full Gmac Trigger kit/Gmac barrel cut to 9inch/Weihrauch Silencer/Custom Home Made Grips/
New TRACER LEDRAY GL2 LAMP 90m Range Beam//HI-Pac

  << Previous Topic | Next Topic >>Return to Index  

760 Trigger creepiness

October 30 2011 at 10:41 PM

dan house  (Login dan_house)
Crosman Forum Member
from IP address 71.210.125.204

Had a few minutes in the shop, worked on the trigger while i was running down what I thought was a leak.

Cleaned up the sear, took about .015 off the top, polished, and no change. Creeps and grinds a bit, then a crisp complete break.

Also noticed that the trigger seemed to move and move and move then break.  Hmmm....

Finally noticed I can seen inside the pump tube thru the sear slot and starting watching what was happening. During cocking, you can see the hammer move back, displace the sear, the sear snap into place and hold the hammer. So far so good. Then pull the trigger, and did this several times cuz I didnt believe it...... the sear pulls the hammer down, alot, as it pulls clear. So when the hammer bottoms out on the inside of the pump tube, the sear pulls free and clear of the hammer finishing the shot cycle.

Ive not been back inside the gun to see what the diameter differences are between the pump tube ID and the hammers OD, and what is acting as the fulcrum for the hammer. And now understand why the trigger moves soooooo much before the shot breaks.

Ok, so how does one stop the hammer from "dipping"down during trigger pull? find and fix the leverage point? button the hammer? modify the hammer spring guide and mount? custom build one?



dr_subsonic's pneumatic research lab
[linked image]
the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

 
 Respond to this message   
AuthorReply


(Login airgunandy)
Crosman Forum Member
206.208.93.60

Hmmmmm.....

October 31 2011, 5:27 AM 

I hadn't noticed the vetical movement of the hammer before. I just knew the take-up (or whatever you call it) of the trigger before it trips is very long, so I changed that (one of my secret herbs and spices). Also polished mating surfaces of the sear and used a little plastic-compatible grease with PFTE on all contact points. Not match grade, but a big improvement.
I thought about removing the little doohickey that prevents the trigger from being pulled while the bolt is open since it has a spring that puts more pressure against the trigger, but decided to keep it for added safety.

I plink, therefore I am.

 
 Respond to this message   


(Login pneuguy)
Crosman Forum Member
68.221.9.77

Why not drill and tap the bottom of the tube for a setscrew?

October 31 2011, 8:07 AM 

Then you could tweak for minimum clearance consistent with free hammer motion. You might have to relieve the back end of the hammer to clear the screw as the stroke progresses, but other than that it should be straightforward.

Something like this?

[linked image]

Steve

 
 Respond to this message   

dan house
(Login dan_house)
Crosman Forum Member
153.90.162.47

Well.....

October 31 2011, 9:26 AM 

hmmm dont see why not, assuming that part of the hammer sets back enough to engage the set screw. Which is easily checked.....

The other thing I was thinking ws buttoning the hammer on both bands. Course the more prudent solution would be to figure out whats letting it rotate in the first place. I have a theory, but I need to look into it more



dr_subsonic's pneumatic research lab
[linked image]
the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

 
 Respond to this message   


(Login airgunandy)
Crosman Forum Member
206.208.93.60

Won't the screw mess with the trigger?

October 31 2011, 9:32 AM 

Looks like the screw is going right up through the top portion of the trigger where it engages the sear.
Or would it actually be behind (or in front) of the trigger?

I plink, therefore I am.

 
 Respond to this message   


(Login robnewyork)
Crosman Forum Member
108.21.102.194

you would have to shave the rear of the hammer for it to pass smoothly

October 31 2011, 9:34 AM 

Steve mentioned that as the action progressed foward depending how u have the screw set it might snag on the rear spring guide area.. otherwise no trig interference.

 
 Respond to this message   


(Login airgunandy)
Crosman Forum Member
206.208.93.60

In the picture

October 31 2011, 9:39 AM 

In the picture the screw (orange) is right in the top part of the trigger where it engages the sear (yellow except in the area above the sear).

I plink, therefore I am.

 
 Respond to this message   


(Login pneuguy)
Crosman Forum Member
68.221.9.77

Good point. Maybe the screw could be located at about...

October 31 2011, 10:10 AM 

...the 45o point and thus clear the trigger on the side?

Or maybe it's just a stupid idea. happy.gif

Steve

 
 Respond to this message   


(Login airgunandy)
Crosman Forum Member
206.208.93.60

Re: Good point. Maybe the screw could be located at about...

October 31 2011, 10:39 AM 

Or one on each side of the trigger? Or would that be overkill?

I plink, therefore I am.

 
 Respond to this message   


(Login pneuguy)
Crosman Forum Member
68.221.9.77

I'd say two would be overkill. Having the hammer off to one side...

October 31 2011, 10:41 AM 

...shouldn't matter much.

[linked image]

Steve

 
 Respond to this message   

dan house
(Login dan_house)
Crosman Forum Member
153.90.162.47

off to the side would work.

October 31 2011, 12:39 PM 

just need to make it stop much hegher in the tube.

My prime suspect at this point for allowing the hammer to move that much at all is the spring guide.

My 22xx and 13xx guns dont exhibit (or at least as much....) this behaviour. and its essentially the same drive train, excepting the spring termination.

Gonna look at the guide, see if I can get it to stay in place or make a mo' better one (hehe or a third option: maybe I'm not reasseembling it correctly, and thats what allows all that movement.....)

 



dr_subsonic's pneumatic research lab
[linked image]
the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

 
 Respond to this message   


(Login robnewyork)
Crosman Forum Member
108.21.102.194

almost easier to change the trigger shape. making a shorter throw!?

October 31 2011, 12:51 PM 


 
 Respond to this message   

dan house
(Login dan_house)
Crosman Forum Member
153.90.162.47

Except....

October 31 2011, 12:55 PM 

the sear holds onto the hammer strong enough to pull the hammer down. when it bottoms out on the pump tube, the sear pulls free of the hammer.

 

its the hammer movememnt thats the issue. Otherwise, yes, trigger mods would clear that up....



dr_subsonic's pneumatic research lab
[linked image]
the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

 
 Respond to this message   


(Login robnewyork)
Crosman Forum Member
108.21.102.194

I SEE

October 31 2011, 12:59 PM 

i wish i could seee pics, mine seems to have almost no tolerance in any direction, very little .matter of fact it was hard getting back together.

 
 Respond to this message   


(Login airgunandy)
Crosman Forum Member
206.208.93.60

Re: Except....

October 31 2011, 1:53 PM 

What if the sear didn't push the hammer up in the first place?
Perhaps shortening the face of the sear a smidgen? If it were not as tall it wouldn't be pushing up on the hammer and dragging it with it when it was pulled down.
Alternately, what if you ground a little off the nose of the hammer where the sear is pushing up on it?

I plink, therefore I am.

 
 Respond to this message   

Anonymous
(Login mav72)
Crosman Forum Member
68.7.252.9

760 Trigger creepiness

October 31 2011, 1:52 PM 

Could you "sleeve" the hammer in that area with a piece of piping or tube to get rid of the "play" or am I missing something? Maybe you could JB weld it to the hammer then drill holes in an "X" pattern from vertical and then press in some pins to make it extra secure and grind down the excess flush... Would that work?

 
 Respond to this message   


(Login robnewyork)
Crosman Forum Member
108.21.102.194

auluminum from a soda can would do the trick , well said anon.nt

October 31 2011, 1:53 PM 


 
 Respond to this message   

mav
(Login mav72)
Crosman Forum Member
68.7.252.9

That was me... LOL

October 31 2011, 2:40 PM 

I forgot to add my name... For some reason it doesn't stay on this computer...I'd change the post and add my name but then your post won't make any sense... LOL

 
 Respond to this message   

(Login Bruce46)
Crosman Forum Member
99.10.200.140

Re: 760 Trigger creepiness

October 31 2011, 2:44 PM 

If your picture is correct, a delrin collar around the hammer would take out a lot of the slop without getting in the way.

 
 Respond to this message   


(Login pneuguy)
Crosman Forum Member
68.221.9.77

Re: 760 Trigger creepiness [Did somebody say: "CREEPINESS?"]

October 31 2011, 6:15 PM 

[linked image]

Hey. It's Halloween! Couldn't resist.

Steve

 
 Respond to this message   


(Login airgunandy)
Crosman Forum Member
65.190.155.55

TRIGGER TREAT!!!! n/t

October 31 2011, 7:28 PM 



I plink, therefore I am.

 
 Respond to this message   

(Login BGRooster1)
Crosman Forum Member
71.90.116.227

Re: TRIGGER TREAT!!!! n/t

November 1 2011, 9:05 AM 

At times these airguns make ya feel like an evil scientist.


 
 Respond to this message   
Current Topic - 760 Trigger creepiness
  << Previous Topic | Next Topic >>Return to Index  

Crosman Corporation 1-800-724-7486