What is the secret to QB Breeches???

[Rob in NC]

Is it just me or is the QB 7X breech just a mystery?   I have tuned all manner of springers... I have tuned PCP's, I have built various conversions from CO2 to PCP/HPA.   

I've worked on no less than a dozen QB7x guns converting to HPA or PCP and each and every time, I have trouble getting the breech on and working correctly.  My latest project has me converting a QB78 Carbine to HPA.  I used a tank block and a 79 tube.  Did some light valve mods... not looking for a lot of velocity here, just wanted a project.  Got her dressed in a nice laminate stock....but.... yet again, the breech is giving me fits.

I put it together and pull back... push forward ...and am 'rewarded' with just a muffled little 'click'... no 'snap'... This happens each time I work on one of these guns.  Eventually, I always get it, but by then I've tried every possible configuration I can think of and never know what I did to 'fix' it.

Anyone else have this issue?

[rsterne]

You have the cocking pins in the wrong place in the bolt.... at least that would be my guess.... Next time you take a NEW one apart, pay attention to where they go....

Bob

[Rob in NC]

You have the cocking pins in the wrong place in the bolt.... at least that would be my guess.... Next time you take a NEW one apart, pay attention to where they go....

Bob

and that makes sense... but I've tried every configuration I could think of...haha...   If I dont get it by the weekend, I'll  just bust open another one and see.   One would think that after doing a dozen of these that a 'smart' person WOULD have paid attention when he took the breech off..... ah well.