Trigger fell out

I have a crossman pulse r78 and it will not shoot ,when you pull trigger it Gus windes oner spring do not egage

With magazine out, what happens after cocking, should get a gush of air, if nothing, spring not latching, or seal leaking badly, have you adjusted trigger, to fine with a spring type, will not latch, so no pressure, can you feel anything happening, nothing at all spring latch, can you feel the pressure of the spring when you cook it.

http://www.gatewaytoairguns.org/GTA/ is good place to start, you will get all the free advice and info you need.
Largest air gun forum, international. Free to join, all you have to do is luv air guns.
Youtube has some good mods but...
This is the best! It's like the Rolls Royce of triggers!
http://charliedatuna.com/GRT-III%20Trigger%20New.htm

I had the exact same problem.. turned out to be that the cylinder wasn't lubricated properly so it wasn't sliding well.. I dripped some lubricant down the barrel and it shot like a champ! (ps, I used the wrong lube and I'm too lazy to look up the correct lube, but either way, that's your problem)

Upon cocking your gun is there the same tension with the cocking spring as there was befor? Also check the condition of your barrel seal for tears or cracks in it.

get a dejamming rod and put it through the barrel because its most likely jammed

The trigger might of slipped off the switch in your gun. it's easy to fix, just take apart your gun slowly so you don't lose any parts and align the hole in the trigger with the small switch in your gun.

Try this link:
http://www.gun-parts.com/remingtonshotgun/Jan22_03.jpg
Hope this helps. :)

Crosman bought out benjamin / sheridan, and they still repair just all their pump guns. The ring sounds like a piece of a pellet, the barrels are silver soldered to the bottom tube, Not lead. Also, the repair kit should not have too many parts, you can only go so far with those guns before needing special equipment to get them apart. Get a hold of Crosman and tell them that benjamin sent you a bad part. They should fix it.
I had an old Benjamin Franklin in .22 cal, it was just a brass tube with a stock and barrel. I sent it to them, to be repaired, and I wanted the .22, because I had the 5mm and the 177. So I got it back, cost $29, New barrel, in .177, soldered on, new guts, new paint, trigger, bolt, the works.. Brand new gun. I told them I wanted the brass and I wanted the .22, They said oops, sorry. I didn't complain, nice old gun. Hope this helps.

HI, I found something on amazon. here: Crossman Air Guns Model 760 Pumpmaster Owner Manual English spanish... . I hope I have helped. cheers