The 1938 is a gun that I want to do some projects with in the future. Been awhile since I took one apart. I’m pretty sure the plunger assy will work. Cobalt will have a better idea. Very interested to see/hear your experience with that idea. Do you think the hop up should be on the top or bottom side of the tube???? I don’t have a clue—-concerning magnets (and many other things). Bought some last year for a G’kids science project. Couldn’t believe how powerful they were. Be a fun thing to test.
Think I’ve figured how to test the hopup using “rubber” insert. I’ve got an older 1938 (needs rebuilt) with the screw out shot tube. Easy to get to. I’m going to cut a notch just ahead of the air tube when extended. Duct tape/ zip tie insert into place for testing.
The gun needs plunger spring Assy replaced. Hoping one of my newer bucks will drop in ?? Thoughts.
On the magnet front, Mike and I got some bits done in the machine shop. One is a 499 abutment for the single shot 105b/499 hybrid. It has a magnet to hold the bb in place with about 4 lbs pull vs about 0.25 lbs from the stock magnet. Hoping to hold the bb in place to allow some compression to actually build before breaking the bb loose. Just a theory to test! I think that the position of the magnet in the 499 abutment helps create a “hop up” like action. It may be part of the reason for their legendary accuracy, the closer fit tube to bb plays a great part as well.
Magnet pic is only started in. It’s pushed in flush. Don have a pic of the completed part.