jjj - 9/22/2009 7:19 AM
I am considering this conversion, from .177 to .22 cal.... ... anything to watch out for?
The Disco uses the "New" breech screw location. You will need to remove the action from the stock.
De-gas the gun! Do not work on a fueled AG...
First remove the safety:
Using a "Bent Pick" you apply pressure to the safety spring end away from the safety button towards the trigger. It will be found inside the seam area of the trigger group just below the safety button. It looks just like the end of a wire...
All screws are Lefty Loosey, Righty Tighty..
Remove the stock:
With the safety removed... The single screw in the fore stock area is all you have to remove to take the stock off...
Remove the Rear screw to the trigger group.
Remove front sight and mini brake.
Loosen and remove the barrel band.
NEXT PART IS WHERE A SPRING CAN FLY!
While holding the rear spring plug. Remove the Rear breech screw.
Set the spring plug and spring aside.
Now you can pull the bolt handle back far enough to expose and remove the small breech screw.
You will have two small seals between the breech and Gas Tube. Both must be in place to make up the seal between the barrel and valve. So don't loose them when you lift off the breech. The go "Soft Seal' in the gas tube and hard seal on top.
NOTE:
If you strip the head of the small breech screw... DO NOT DRILL IT OUT.
Instead... use a small precision screw driver just large enough to press in to the stripped Allen head.. Gently tap with hammer seating it into the screw. And un-screw it... The breech screw will need to be replaced and is not common hardware. You will have to get it from Crossman or an AG shop...
Loosen the small set screw on top of the breech to remove the barrel from the breech.
Finally... Remove the handle from the bolt. Lefty loosey.. Pull the rear plug out of the breech and slide the bolt out the rear.
I wish I could say... Reverse instructions for assembly... but there are a few tips and tricks to getting it right the first time....
Installing your .22 cal barrel and bolt.
Using a little divers grease (Silicone Grease) goes a long way in assembling and maintenance of all seals...
I get mine at a local dive shop... it can be ordered on-line at
http://www.ninjapaintball.com/productDetail.asp_Q_catID_E_91_A_subCatID_E_78_A_productID_E_113Put a thin coat of silicone grease on the bolt o-ring and slip it on the bolt.
Re-install bolt into breech and attach the bolt handle. Just a dab of loctite blue or purple on the threads will keep it from loosening while cycling the action.
Close bolt and insert the new barrel to where it is tight and aligned with the transfer port. Lock it down with the set screw in the top of the breech. The bolt must be closed to achieve the proper seal with the barrel. This can be adjusted on the gun once assembled.
Here is where the divers grease comes in handy…
Dab a bit on the soft and hard seals… This will hold them in place while installing the breech and barrel.
Soft seal in the gas tube and hard seal on top.
Re install the rear breech plug lining up the hole for the rear breech screw.
Make sure the bolt is closed.
Set breach and barrel on top of the gas tube carefully lining up the transfer port seals.
Temporarily place the rear breech screw through the mounting hole.
Gently slide back the bolt to expose the small breech screw and slide the hammer back.
Install the small breech screw just slightly snug enough for you to close the bolt.
Push the hammer forward.
Gently pull the bolt back again to set the hammer in the proper place.
Finish tightening the breech screw. Not to tight! If you are using a long .05 Allen key… just hold it at the end and when it flexes… it’s tight.
Now you can remove the rear breech screw and install the Hammer Spring, Plug, Rear Breech Screw, Rear Trigger Group Screw and stock. Nothing special in that…
Re-installing the Safety….
With a straight pick… Insert the pick inside the Safety button hole. Pull spring towards the trigger enough to get a finger nail on the end of the spring to pull it far enough to push the safety button back in.
Barrel seal adjustment…
Cycle the bolt back and forth locking it down. If it is loose… You now can loosen the small set screw on top of the breech and gently push the barrel into the breech, holding it while you tighten back up the set screw. The idea is that the bolt should not flip up when firing.
Now install the barrel band, Mini brake and front sight.
Fill her up.. and re-sight her in with .22 cal pellets… My disco loves JSB Exacts…
I hope this helps...
