The New Hotness

Mary made a frame weight to maintain tension on the fabric in the HQ Sixteen longarm:

It’s a sturdy cloth tube filled with BBs, somewhat like a grossly overweight door snake (a.k.a. draft stopper).

The bottle of 6000 copper-plated steel BBs arrived in an overwrap bag of the sort Amazon applies to all bottled products. This was a Good Thing, because the scrap of packing paper did nothing to cushion the bottle in an otherwise empty box. The bag contained most of the shattered cap and a few BBs, with escapees rattling around inside the box and surely a few left along the way.

So I conjured a replacement cap from TPU:

Crosman BB bottle cap - solid model - build view — Crosman BB bottle cap – solid model – build view

It fits around the bottle neck and snaps onto the spout just like the original:

Except this one is unbreakable.

The strapless TPU cap was a quick test to verify the fiddly shoulder snapping onto the bottle snout:

Crosman BB bottle cap - solid model - section view — Crosman BB bottle cap – solid model – section view

As it turned out, we poured all 6000 BBs (minus those few lost-in-transit strays) into the cloth tube, but the bottle will come in handy for something someday.

The OpenSCAD source code as a GitHub Gist:

	// Crosman BB bottle cap
	// Ed Nisley – KE4ZNU
	// 2026-02-22

	include <BOSL2/std.scad>

	Layout = "Show"; // [Show,Build,Section]

	/* [Hidden] */

	ID = 0;
	OD = 1;
	LENGTH = 2;

	HoleWindage = 0.2;
	Protrusion = 0.1;
	NumSides = 634;

	$fn=NumSides;

	WallThick = 1.0;

	Heights = [1.2,2.0,13.0,WallThick]; // for easy tweaking

	Ring = [34.5,39,WallThick];

	Strap = [70.0,5.0,Ring[LENGTH]];

	CapOAL = sum(Heights);

	//—–
	// Conjure it with magic numbers

	module Cap() {

	tube(Heights[0],id=16.8,wall=WallThick+0.6/2,anchor=BOTTOM) position(TOP)
	tube(Heights[1],id=17.4,wall=WallThick,anchor=BOTTOM) position(TOP)
	tube(Heights[2],id1=17.4,id2=14.0,wall=WallThick,anchor=BOTTOM) position(TOP)
	cyl(Heights[3],d=14.0+2*WallThick,rounding2=WallThick/2,anchor=BOTTOM) position(BOTTOM)
	cuboid(Strap,anchor=BOTTOM+LEFT) position(BOTTOM+RIGHT)
	left(1.0)
	tube(Ring[LENGTH],id=Ring[ID],od=Ring[OD],anchor=BOTTOM+LEFT);
	}

	//—–
	// Build things

	if (Layout == "Show") {
	Cap();
	}


	if (Layout == "Section") {
	difference() {
	Cap();
	down(Protrusion)
	cuboid(2*Strap.x,anchor=BOTTOM+LEFT+FRONT);
	}
	}

	if (Layout == "Build") {
	back(Strap.x/2)
	zrot(90)
	up(CapOAL)
	yrot(180)
	Cap();
	}

view raw Crosman BB bottle cap.scad hosted with ❤ by GitHub

The New Hotness

Crosman BB Bottle Cap