RG-G Drum retro-engineering

Probably the original RG-G feed design was not fully resolved at the time of the drawings.
But after some quick looks my finished assembled feed mechanism, I came up with the following obvious details.

As the rimmed 22 cartridges rotate around the drum with +.120\" of \'single filer\' rib clearance for the feed arm/rims, they stagger/stack on top of each other(rims are only about .040). See pic.
When they get to the feed drum which only has .060\" clearance for the rims, depending where they stacked themselves up they jam up tight. When a bullet tries to feed and it\'s rim is not in line with the rim groove, it don\'t fit. In the pic you can see the staggered/stacked rims(3@.120) trying to fit into the .060 feed drum rim groove.

So I\'m thinking of putting a bevel on the feed drum from the .120 \'single filer\' rib dimension to the .060 feed drum inner dimension.
This will ramp the cartridge rim into postion in the feed drum no matter where it lands on its \'feed drum\' approach, from the single filer groove.

Next is the .120 height of the pins that actuate the feed drum, not quite high enough to catch the feed drum pins. My parkerized pins are like anti-skid and lock up instead of slip nicely into position. I\'m going to wait till i get the bullets to come out of the feed drum properly until this is re-engineered because the spring loaded feed arm may push the feed drum/pins around a little more and catch properly.


Working with the drum magazine door off helps a lot to see what going on(or not!) with the mechanism.

That\'s an interesting looking yoke you have at the end of your frame rails, what\'s its function?  Is it tied into the elevating mechanism?
Dick C. (gatguy)  :?:  

Look fir this thread \'Mil-Surplus Non-Traditional Tripod Mount\' it explains it.

Spent about a week troubleshooting this drum feed mechanism, it has it\'s problems. The cartridge rims stack on each other at the feed drum so a 45 degree and a 30 degree angle will give the clearance needed to prevent that jam. The angle will also guide the rim to where it belongs at the back wall of the drum as the cartridge drops down into the breech.


On the one side of the rotating feed drum rib the sharp corner pinches the round(jam) when it grabs it(severe angle at times), so a flat is milled to spank it into the cartridge groove instead of trying to tightly grab it. On the other side of the rib a radius is used to let the next cartridge effortlessly load into a feed groove and then use the force of the drum magazine spring to snap the feed drum(and the 1/8 diameter pawl) into the next \'ready\' position for the rotating breech. That \'snap\' into position makes it sound like it means business!


I\'m still experimenting with the radius(at 3/16R now) and determined to get the drum magazine feeding correctly. So far so good. The rims make the cartridges load on an angle at the drum,it can be a severe angle. Just add .020 X number of cartridges.