It seems like disassembling these rifles has the potential to cause headspace issues when they are reassembled, so you'll want to test-fire it.

I found two at a local shop the other day for about $300 each. Was neat to handle one again after about 25 years.

Cas, should you need any parts they are available on the auction site. Both the inner mag tube and the outer tube are available.

I believe new reproduction inner tubes may be available, or at least were fairly recently.

I tested the rifle last night, functioned just fine. One thing I'm always taken by is the distinct sound the rifle makes, it's like no other .22 I've fired.

Some relatives still have them. I remember them in department store catalogs. Pretty sure they load from the end of the stock.

A few years back I was working in a gun shop as the guy who cleaned and overlooked the incoming used firearms.
One day some elderly folks dropped by wanting to sell a deceased members firearms, it was quite the older “cooler” stuff from the 60s and 70s including two of these Nylon 66s, both in black and one with a small “rim fire” scope attached.

Being that guy I had to take them apart to clean them and was extremely thankful that the parts/disassembly owners papers were included!

Just saw one advertised on VA gun trader for $650.00

An update on the old Nylon 66 Apache I bought recently. I found a good stock from the same time period and today I disassembled it down to the bare frame. I cleaned all the parts, replaced some pieces and put it all back together in the new stock. It function checked fine but the Northeaster is still dumping rain on us so a live test fire will have to wait. I don't expect any problems and it wasn't terribly dirty. Barrel is very clean with no visible pitting or damage to the bore. It wasn't a nightmare to put back together but I was glad to find a good YT video to help. I'll be back with a range report.