Air Gun Home :: View topic - DIY shroud for 1377, cheap and effective!

domer_pyle · Senior Member

Materials needed that can all be found online or locally (for most), not including tools:

1.125" x .058" x 1.009" ID aluminum tube

1" x .035" x .93" ID aluminum tube, if you care to go the route of baffles and need spacers that don't compromise much volume

.5" x .03" x .44" ID tube, I used brass because the closest ID for
aluminum was .444"

2-3 stainless steel solid one-piece shaft collars 1" OD x .5" ID

1-2 black oxide coated one piece shaft collars 1.125" OD x .5" ID

1-4 1" x .25" ID nylon washers if making baffles

2-4 1" x .1875" ID stainless fender washers

Measure how much barrel sticks out past the barrel band and cut the brass tube to this length. Slide the tube onto the barrel, keeping about 1"-1.5" of the barrel exposed in front of the barrel band. Use a piece of tape on the barrel to mark how far you slid down the tube.

Mark the outside of the tube where the muzzle will end inside the tube. Remove the tube and drill a .25" hole on the top, bottom, and sides of the tube just in front of where the muzzle will sit. Ream the inside if needed.

Pictured with shaft collar in place, tape is to snug the collar inside the tube.

Slide the tube back onto the barrel to your tape marker.

Slide on one of the 1.125" shaft collars flush to the end of the tube closest to the breech, put some blue lock tight on the threads of the set screw and give it a good twist, but open the pump arm first to be sure the collar is out of the way.

Slide on one of the 1" shaft collars right up to the first one, lock tight the set screw and tighten it up. The pressure from these two set screws will keep the tube in place on your barrel.

Slide another 1" shaft collar onto the brass tube but leave it flush to the muzzle end. The holes you drilled should be between that collar and the muzzle of the barrel. This lets the initial blast of air escape back into the rear of the shroud because the front shaft collar will act as a wall keeping the air from traveling forward.

This is how your collars should be arranged

Now all that's left is cutting the 1.125" tube to your desired length. It's up to you how far past the inner tube you want the shroud to extend and whether or not to baffle the extension.

I put three small pieces of duct tape on the 1" shaft collar closest to the gun so the 1.125" tube is basically press fit on.

Once the outer tube was in place I dropped in a 1" x .1875" ID fender washer that sits against the end of the inner tube and shaft collar, acting as a baffle to help convince air to escape back through the holes in the brass tube. If you decide not to bore out the washer make sure you won't have a baffle collision!

Measure the depth from the edge of the 1.125" tube down to the washer you dropped in and cut a piece of 1" aluminum tube to .125" shorter than your measurement (you can figure out how to make baffles and spacers if using them). Slide this piece into the 1.125" tube.

To close up the end I bored out a fender washer to about .25" and covered the very edge in Gorilla Glue, then set it in place overnight. I wrapped paper around the end to act as a guide when I file the end flat and I plan on putting some type of cap on there to hide the glue job

Here she is for now next to a 397 for size comparison, my barrel is the full 24" so the shroud got a little lengthy but it's now quiet enough that my 9 month old could sit a few feet away while I took a couple shots out the window and not even jump. The only down side is the gun is no longer a tack driver at 30 yards with the cheap Crosman milk carton pellets, but the CPHP seem to be doing just fine.

Now to find some spray paint and make this thing look like it belongs on the gun!

coalchamber · New Member

Wow nice work and nice pics! thank you