This may be old news, but in my unsuccessful search for Tapco Galil mags, I came across the Tapco M85 mags that looked identical.  They even have the same cage code but the front locking lug is slightly thicker.

I decided to give it a shot when I found them in stock at Numrich gun parts.  Well they arrived today, and after some quick grinder work, they all fit in both of my Galils.  I'll hopefully get to test fire them over the weekend, shot them today, they all work great...

We shall see.
Pictured
Top mag is a grinded M85, middle mag is stock M85, and bottom is Galil mag.
Attached File

Did you use an actual galil mad as a guide, or trial and error until it worked?

I used the Tapco Galil magazine as a guide and made a mark on the M85 magazine.  Then slowly ground the mags down until they fit.

Obviously I didn't get them all exact, but the variance seems to be about what the variance is in Milsurp Galil, and Tapco Galil that I had.  I have 10 metal mags, and 5 Tapco mags, and now have 10 more converted Tapco mags.

I am considering picking up another 5 metal mags just because I have OCD

Nice!

FYI: CAGE (Commercial and Government Entity) code is a designator for the company, not the part. So both mags would have the same code (designating Tapco as the source).