Extreme Crosman Modifications
.50 Cal Muzzle/Breech Loader
Transfer Port Setup
You'll want to remove everything from the gas tube as you construct the transfer port. Failure to do so will melt the seals in the valve, rendering it useless. Drill out the original transfer port hole to tightly fit a length of steel brake line. Sand the gas tube down to bare metal around the enlarged hole. Cut a 1/4" length of steel brake line and sand it as well. Place the piece of steel brake line into the gas tube, making sure that there is plenty of clearance for the valve. Apply flux and silver solder the two pieces together.
Constructing the barrel
The main catch to the barrel assembly is to cut the barrel long enough to clear the rear of the gas tube. If you neglect to do so, the endcap will raise the rear of the barrel, causing gas leaks and making the gun shoot low. BTW, the above picture is of the muzzleloading version. Stand by for the breech loading version which is currently under construction. To give you an idea of what the breech loading version should look like, go over to the homemade airgun section.
Drill a hole in the barrel to accept the transfer port, making certain that the endcap of the barrel will clear the rear of the gas tube. At this time, you will want to silver solder in the endcap or breech assembly. Make sure that the pipe is sufficiently sanded and fluxed. This bond is very critical, since you dont want to wear this part of the gun in your head! If you are building the muzzleloading version, an important safety mod would be to drill a hole all the way through the cap and barrel and secure it with a nut and bolt.