The (new) Crosman Forum, your first and last place for all things Crosman


The New Year means its time for new gun pics.
Got something cool?
Something Classic?
Something werid?
Send it and we’ll use it up top
 Return to Index  

Modding tube bulk for power how to... Photo intensive.

November 24 2005 at 11:14 PM

Biohazardman  (Login Biohazardman)
from IP address

Have been asked about this many times will put it on my site soon but for now.

How to mod tube bulk for power.

The Tube bulk cap Brian and Associates as well as others sell this as part of a two piece tube bulk powerlet eliminator.


Drill 1/4 inch hole all the way trough the cap.


drill 25/64ths hole about 1/4 inch into the rear portion of the cap.


Cut two or three treads from the cap.


Drill out extra material from the front of the cap for more charge volume.


Cap from the rear


Cap from the front


Now combine this modded cap with the mods already available for the valve body ie; porting, stem mods and a lighter spring for some decent power upgrades. If you choose to use the stock Crosman tubes at high pressures such as 1200 to 1500psi be sure to pressure test them with the valve and cap installed. The valve and cap should be secured for safety. Just because some of us have used these mods at the mentioned pressure does NOT mean all of the tubes are safe at these prssures.

photo power bulk valve_zpsyvedxhov.png

Don't blow yerself up be safe know what you are doing or just plain don't do it.


I used to have a life. But now I have the forum. I am a sick man?


This message has been edited by Biohazardman from IP address on Jun 21, 2015 10:58 PM

 Respond to this message   

Crosman Corporation 1-800-724-7486

This forum is not affiliated with the Crosman Corporation in any way// Information presented in this forum is intended for informational purposes only; use at your own risk//Posts made to this forum are solely the opinion of the individual member