To all readers: I like John Wick. I also like revolver projects. This project is no more connected with Mr. Wick than that. Please enjoy. And if you know Mr. Wick, tell him about this project, I'd love to hear his thoughts.
We ended Part II of the build with the laser clearing the ammo tubes front mount and a plan to attach the tube holders to the front and rear mounts.
The idea was to permanently attach 4/40 coupling nuts to the head of the bolts used in the front QD mount and the rear red dot mount, as shown in expanded view below. Long 4/40 button head screws would then extend through the ammo tube brackets and tighten into the coupling nuts.
I JB welded the coupling nuts onto the mount bolt heads, fed the 4/40 screws through the ammo tube brackets and...... The coupling nuts hold the brackets way too far from the gun's barrel.
As you can see below, Mr. Wick would not approve.
I wondered if the coupling nuts would have this affect, but it was hard to know for sure without assembling. The goal is to mount the ammo tubes as close to the revolver as possible, while still allowing the cylinder to swing open.
So, I tried again.
This time I made my own coupling nuts from two small 4/40 jam nuts. As you can see below, this setup also holds the ammo tubes further to the side of the gun than is necessary for cylinder clearance, so it was time for idea #3.
The astute readers among us, may be asking, "Uncle Fudd, why not just use a long bolt that fits in the front QD mount and rear red dot mount? What's with all this coupling nut and JB Weld fuss?"
Well, dear friend, it's because I was concerned that the bolts that the front and rear mounts take (8/32 and 6/48 respectively) are too thick and would impede the movement of ammo in and out of the tubes.
I've been using the various coupling nut setups to step down the front and rear mount bolts to 4/40, which has a small enough diameter to barely skim the inside of the carbon fiber tubes. You can see this in the image below with the ammo tube bracket removed.
Displeased with the results of mounting attempts #1 and #2, I decided to give the bigger bolts straight into the mounts a shot.
A few scrap test gave me confidence that the large bolts wouldn't impede the ammo or spring moving in and out of each tube, so I drilled the holes between the tubes a little wider and test-mounted the front of the tube with the QD mounts' native 8/32 bolt.
As you can see below this style of mounting: looks way better, is more secure, and gets the ammo tubes much closer to the revolver. It'll be even closer to the gun once I have the same setup for the rear mount.... the 6/48 bolt hasn't come in yet. Turns out, that's not a very common thread size.
Once the 6/48 bolt comes in I'll get the rear ammo tube mount locked in. Then I'll turn my attention the mechanism that will both hold the ammo in the tube (against the spring pressure) and allow for a Mr. Wick-like person to quickly draw 1x round at a time.... Something that has already required much mental rumination.