To make a accurate clone how hard is it to find parts?

Hard.

You'll search for a long while to find an early square forge 603 receiver, and just as long to find a bolt carrier group.   Barrels are rare as well, but they're the easiest of the bunch.


Here's my former XM16E1 project


The BCG is a transitional. Anachronistic to the rest of the build. The barrel is an M VP. Early bend gas tube. No drain hole handguards.  I ended up finding a square forge 603 upper for this but I ended up throwing a C MP C barrel on it and making a 1968-1969 clone, and the early parts went to complete an early 604.

As stated the correct parts get harder to find as time expires.  Haven't seen many early bend tubes for sale lately.  Early chrome BCG usually has been the hardest most expensive piece less the barrel.  Not that they don't exist but most won't sell them.  Transition parked BCG not hard to find.  Always the pig in the poke but lots of competition for chrome serrated BCG purchase usually.  Barrels lately have become the most expensive part.  Seen the nice one's bringing over $400 pretty quickly and even rough at best bringing $300 plus.  Being exact will take time to complete more than likely but good luck.  Probably the most sought after build of the retro platform  AR's.

Couldn't somebody make us reproduction early gas tubes ?

most probably don't go the repro route since it's something that isn't seen.  if you find an original, it's nice knowing that it's original but if it's not, it's not something anyone would notice unless you removed the handguards.  kind of like grip screws.

Ya, your right , it isn't something I pay any attention to for that reason,,
Can't see it.   And a original is just to expensive in my opinion for what it is.
But if somebody were to make a reproduction , I'd buy one

I have made a handful, but there was no demand, so I gave that endeavor up.

John Thomas

Seems a lot of us lucked into parts. I walked into my LGS few years back and mentioned I was attempting a retro build. Owner came out from the back with a box containing a complete 604 upper with chrome serrated BCG, early bend tube, and a MP C barrel.
Box had a type D stock and A1 pg as well, he said this box was sitting in the back for almost 20 years. I offered $400.00 for the box and he quickly accepted, now that I'm thinking about it....he might of gone lower. That box helped me out with xm16 and a 604 build.

ETA: Now there have also been times where I was looking for say an early upper and paid over market for it. I haven't built a retro in over a year because parts dried up, prices on retro parts are extreme and I just haven't walked into a deal. Good luck with whatever you decide on building and hit up any old gun shop you can find.

Am beginning to wonder what my original XM16E1 upper is worth...not that I'll ever sell the gun, but wow, things have sure gone up last few years. I need to get into something cheaper to build.