leak when pressure on trigger

[stolz]

i just finished building an 68 classic for my brother out of misc. parts iv bought from ebay and around on other forums. After it leaked the few first times i just got it in working order, if i apply any pressure to the trigger it will leak down the barrel. If i pull the trigger fast it will fire but give a small hiss while im pulling the trigger to fire. Do i need a different spacer or is something else going on?

im testing with 12grams because i dont have any other air source atm.

[MournBlade]

Check for wear on the sear and bolt. Try a shorter power tube spacers until the leak stops. If it doesn't stop, replace the sear and/or bolt. These are normal wear items so its best to buy new. IME a sear is usually good for about 500k shots before the wear becomes apparent. Most mag owners never see this happen as they have upgraded in one form or another throughout the life of their mags.

[Ruler_Mark]

is this lvl 10? you mighht have bolt stick

[MournBlade]

I'm assuming a L7, Since he mentioned classic.

[stolz]

its a normal lvl7

i tried a new bolt and it stayed the same, Also a used a shorter space and it still does it.

[Pullman]

Part of your problem might just be the co2. I realize classics can run on CO2, but I have found them to be pretty fiddly. More than a few times I have had wierd things happen while running a mag on CO2 that just disappeared when I switched to HPA. Also you will be lucky to get 20 shots off 12 gram, and those would need to fired slowly.