I have an RPG2 PG2 round minus the propellant section but need final measurements in order to reproduce. If anyone has or can get me dimensions of the aluminum part sitting immediately aft of the fins but before the black powder charge, I’d be eternally grateful. I solemnly swear I am up to no good.

Have you contacted Robert Bowman? If all else fails, I'm pretty sure that Bob has multiple intact (but inert) rounds in his collection. One was up for sale a while back.

I can get them for you in a week or two, if you don't find them somewhere else.

Haven't found them yet. I can wait.

In my dirty little hands I have a Chinese training round with the threaded boss to screw the launch motor onto, and the transverse mounted primer.

Since you're in Phoenix, I can deliver it to you...but only if you promise to deliver excellent product to the eager public

A friend of mine has a tail fin assembly with the aluminum base on it, which I could probably borrow... but this particular piece is entirely turned aluminum, and much more precise than the stamped fin assemblies.  It will be much better to get measurements off of.  I bought it specifically to precisely measure the distance from the indexing pin to the center of the primer (which is on the opposite side, of course).

I have a metric butt-ton of stamped fin assemblies, but none of them have the aluminum bit on the back.

I solemnly swear I'm up to no good

I was going to send you a picture by IM, but I just learned you have to link to a URL in IM.  I would post it here, but it's too big, and I don't know how to fix it on my phone.  I'm pretty sure this is what you need.

I'm in Sierra Vista right now, but I'll be heading to Phoenix in a day or two.  I could mail it, too.  My place is in South Scottsdale. Shoot me an IM and let me know how to proceed.