Help me with a question...


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gspn
December 30, 2013, 12:04 AM
Today I tried to perform a trigger job on my Crosman TR77 NPS. Long story short…it went wrong. I took too much stuff off the trigger and spent several hours with no schematics trying to figure out how it should all go back together.

I got the pieces back together…(not sure it's correctly assembled)…but now…the gun won't cock. It's a break barrel design. I can break the barrel open and there's pressure, but it won't lock open to where I can load a pellet…it just springs right back with full pressure. Any ideas on what I screwed up?

Anyone have a schematic of the trigger assembly? The owners manual has nothing.

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Mousegun
December 30, 2013, 08:50 AM
You may have seen this before but if not, it may help.

http://www.gatewaytoairguns.org/GTA/Parts_Schematics/CROSMAN,_GAMO,CHINESE_TRIGGER.pdf

Another thing you may try, assuming you got everything back in place properly, is turning the adjustment screws to see if what you did pulled the adjustments out of range and all that may be needed is a tweak on the screw or screws to get back in so that the sear grabs what it is supposed to.

gspn
December 30, 2013, 10:04 AM
THANK YOU!!!!!!!!!!!!!!!

Last night was about three hours of trial and error trying to get parts back together. The trigger parts basically came apart like a claymore...parts went everywhere before I could see where they came from...so I didn't have much hope of putting Humpty Dumpty back together again.

Armed with your pics I have renewed hope that I can get the gun back in action. I was ready to throw it in the trash last night.

Chevota
December 30, 2013, 07:06 PM
How did the trigger job go? Success? If not I have info for doing a trigger job on that trigger, several different options from a basic 30 second fix to making it like a gold aftermarket or better.

gspn
December 30, 2013, 07:53 PM
Still struggling. The instructions I got from Mousegun are awesome…but they are pictured from the perspective of the trigger pack being off the gun and re-built from the bottom up. I can't get my trigger pack off the gun…so I'm trying to have to figure it out in reverse.

I'm a mechanical guy…I work on my truck and car and bike all the time…but this trigger pack has me confounded. I have no idea what I'm doing. :confused:

gspn
December 30, 2013, 08:42 PM
Now I have all the trigger pieces back together…but the gun won't function.

The safety seems to work, the trigger seems to have a normal range of travel…but I can't cock the gun and therefore it won't fire.

Normally when I cock it there's a lots of pressure, then it "snaps" into the open position for loading.

Now when I cock it there's some pressure (nothing like normal) and the gun won't "snap" into the open position for loading…there's just constant tension and if I let go of the barrel it will return automatically to it's closed position.

I have no idea what to do. Might have just ruined my first air gun with a "10 minute" trigger job that's consumed 7 hours over two days.

Chevota
December 30, 2013, 09:15 PM
It's not ruined, probably just a spring in the wrong place or something. I noticed in that guide it showed a sear upside down in one pix, that would do it too.

write me at chevota at hotmail and I'll send you some pix that help

btw, you have to take the gun apart to get the trigger housing out, meaning puling the main crosspin and releasing the spring. A Crosman nitro needs about 170lbs or so to take the pressure off the spring to remove or reinstall the pin. I can do it in seconds with no tools, but if it's your first time it can be hard to get apart, and extremely difficult to get it back together.
You can do a trigger job without taking the trigger housing out, but imo it's much easier to work on when it's out.
Also imo the gun should be given a new main seal while apart, and fixed so it won't tear up the new one like the original is.

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