To use this block with a 12g CO2 model, a PCP or bulk-fill style valve is required. We have Discovery valve caps listed that convert your valve to work with this block.

This is the Magnum Tank Adapter made of 7075-T6 aluminum. It fits tanks up to 2" OD. It threads directly into Crosman/Benjamin 7/8" OD tubes including 2240, 2240XL, 2250, 2260, 2300T, 2300S, 2300KT, 2400KT, Discovery, Challenger, Maximus, Fortitude, 1701P, 1720T, Marauder Pistol and many related models that share the same tubing and thread size.

If using the factory valve-mounting screw, this setup is safe for CO2 or an HPA tank regulated to 1400 PSI or less. For higher pressures you need a PCP valve with three custom valve-mounting screws, if done correctly that can handle up to 3000 PSI.

You can either drill the anchor-screw hole in the tube as described in the next paragraph or install it with threadlocker instead. The block will thread past the point where it's straight so you thread it all the way until it touches the tube, then back it off a partial turn until it's straight and let the threadlocker set. Only use a small amount of medium-strength threadlocker so the block can be removed if needed in the future. A heat-gun may be needed to remove the block after the threadlocker has set, only heat it enough to be able to turn the block, the less heat the better. Do not use a torch or any heating method hotter than a heat gun, the tube can lose it's structural integrity if heated too much, heat evenly around the diameter of the threaded area.

BLOCK INSTALLATION TIPS & DRILLING THE ANCHOR-SCREW HOLE: Thread the adapter all the way in, then back it out until it points straight down. Mark the center of the hole 1-1/64" from the back of the block, not the front of the tube.  Deburr the inner edge of the hole after drilling so the o-ring on the adapter doesn't get damaged during installation. CO2 models have tubes lacking a chamfer at the end of the internal threads, you may not be able to get hard o-rings to go in, so only 70D should be used. You may need to tap the block in lightly with a rubber mallet, block of wood or your hand to get it started into the tube without pushing it past the anchor-screw hole, then push the o-ring under the edge of the hole with a small slotted screwdriver to prevent it from being cut. The screw is T10 drive with a head diameter of .271". The hole should be .275" - .281" (9/32) to fit in a recessed fashion like PCP valve screws do.

For regulated tanks, install the tank empty, then fill it. For CO2 tanks, use an on/off valve attached to the pin valve so you can install the tank, then turn it on. It's nearly impossible to install a tank with high pressure or CO2 in it, as soon as the block starts to open the pin-valve the threads lock-up tight before it's threaded in far enough.