The body tube is 3 7/8" in length
The slide in this kit is 1/64" plywood not plastic
the exhaust hole(s) are 1 1/2" from one end of the body tube , on each side and are 1/8" in diameter
There's 2x 12 " x 3/8" x 1/64" plywood strips
HTH

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"Old Rocketeer's don't die; they just go OOP".....unless you 3D print them.