CROSMAN 1377 ISSUE

[ironsights]

my 1377 newer version, just started to go off while I was pumping, I cock it, insert pellet, pump 5 times, it shoots out pellet at a low pressure while pumping, happens at the 5th pump. Safety is on too. I've never pumped it more than 8 times. Bought it just 2 weeks ago at a canadian tire. Less than 300pellets shot. 
What could be wrong? accuracy is amazing, simple and fun to shoot.

[happymecanic]

How old is your newer version 1377? Is it made in U.S.A. with ''globally sourced parts'', or maybe made in China?

My guess is too loose machining tolerances, when it starts to have a certain amount of pressure the gun sorta ''twist'' and allows the sear to let go. I may be wrong though.

Have you tried not cocking before pumping? If so, what happens?

Have you checked if all the screws are tight?

[ironsights]

it says 1377 classic on the box. all black color including bolt. the foregrip has the deep groove on each side. Made in China on metal frame

Tested it BY pumping first, safety on, then cocking. Its ok. I was told to cock first then pump, it's safer and better for these guns. 

How old is your newer version 1377? Is it made in U.S.A. with ''globally sourced parts'', or maybe made in China?

My guess is too loose machining tolerances, when it starts to have a certain amount of pressure the gun sorta ''twist'' and allows the sear to let go. I may be wrong though.

Have you tried not cocking before pumping? If so, what happens?

Have you checked if all the screws are tight?

[BerkshireHunter]

Well obviously, be careful about loading it and handling it... I dont' think I've ever heard of one going off that easily. Now if you had polished the trigger and reduced the spring tensions, it might be a "light trigger" to be cognizant of.
But a new gun going off just pumping? Yeah, sounds like the hammer is slipping way too easy. I would suggest taking off the grip frame panel to look at the setup, maybe the sear is defective or a part is broken?
I'm sure calling Crosman would work too but I wouldn't be surprised if the issue becomes apparent upon a rudimentary disassembly.

[Back_Roads]

 I have only experienced this with old self cockers

[BerkshireHunter]

I'm surprised more people haven't chimed in, could be the summer distractions. Keep us posted what you find out or if Crosman fixes it.

[chutesnreloads]

This made me want to check my new 1322. Not doing what the OP described BUT....
I put a couple pumps in it and load a pellet, then pull trigger while holding bolt handle and ease the bolt forward to "decock" it.
Found in this position it will fire even with safety on. Can push the bolt forward a little more and seat it and it won't fire.
My older a few years 1377 does not do this but it has a BAKER aluminum breech on it

[Spooner]

This made me want to check my new 1322. Not doing what the OP described BUT....
I put a couple pumps in it and load a pellet, then pull trigger while holding bolt handle and ease the bolt forward to "decock" it.
Found in this position it will fire even with safety on. Can push the bolt forward a little more and seat it and it won't fire.
My older a few years 1377 does not do this but it has a BAKER aluminum breech on it

Very interesting...
I just did this with my two modified 1377's, my modified 362, and my highly modified 367. With the guns pumped and the bolt de-cocked. I tried this with and without safety, with the bolts not seated... and no discharge either with the safety on, or off.

[Spooner]

it says 1377 classic on the box. all black color including bolt. the foregrip has the deep groove on each side. Made in China on metal frame

Tested it BY pumping first, safety on, then cocking. Its ok. I was told to cock first then pump, it's safer and better for these guns. 

I can see where cocking first might be better for the gun by taking pressure off of the valve spring. All of mine have lighter valve springs and have to be cocked first. Where safety is concerned, in your case, probably not if you are loading a pellet as well and it is discharging while pumping. Have you tried the "bump" test? My suggestion is the same as mentioned above. Check to make sure all the bolts are tight. Take the trigger apart and check the components, particularly the sear and check the engagement area on the top rear corner. Maybe there is burr or some other defect causing it to lose its hold on the hammer. What you describe sounds a lot like a sear that is set too light, but in a new stock gun I do not see how unless the sear is defective in some way. 

It will be very interesting to learn what you discover is causing this.