It’s been a bit now but I thought I saw a post about building a fancy speed loader fill tube for loading BBs. It described the proper length of the tube for 50 BBs and even had a nifty block on the end to keep the ram rod together. I can’t find the post now. Does anyone remember what I’m talking about or am I crazy?
I don't know the specific post you're talking about, but I was always taught 10" for a 1 unit cannon magazine. So I'd imagine the same for a filler tube. (.177 x 55 = 9.73~)
By the rules a 50 BB magazine is allowed an OVER-FILL of 5 BB's This allows a margin of error in a fill
Here are some pictures of mine, which is pretty common design It uses 3 sequential diameters of K&S brass tubing. The largest has an ID to hold BBs, then the next two smaller sizes. The middle size is used to make a stop at one end so the inner tube stays attached. You need to account for the stopper length when making the outer tube. Overall tube, with inner tube retracted. the stop on the end prevents the inner tube from pushing too far into the mag Largest tube size (7/32) Smallest tube size (5/32) mid tube size (3/16) I drill a hole marked for a 1/2 unit gun, so I can set the plunger position when filling the tube next to ruler Tube stowed hope this helps