THESE ADAPTERS DO NOT FIT COTHRAN TUBES. HE MAKES HIS TUBE-THREADS TO TIGHTER TOLERANCES THAN CROSMAN/BENJAMIN DOES. WE MAKE OUR ADAPTER THREADS OVERSIZED TO FIT CROSMAN/BENJAMIN TUBES TIGHTER. HIS TUBES ARE TOO TIGHT FOR OUR ADAPTERS.
This is the large version of our Magnum Tank Adapter, it mounts tanks up to 4.5" OD. This is the strongest, safest tank block design in the industry. It threads directly into 7/8" OD Crosman/Benjamin tubes including 2240, 2250, 2260, 2300 series, 2400KT, Discovery, Challenger, Maximus, Fortitude,1701P, 1720T and Marauder Pistol. A 1" diameter shroud or muzzle brake has about 1/8" clearance with a 4.5" OD tank. It has an anchor-screw on the left side to lock it in a fixed position. You can use medium-strength threadlocker on the threads if you don't want to drill a hole in your tube, this is to prevent wear of the threads and stop the block from twisting out of alignment.