Erma 22LR magazine fit

[Kiwi]

Q. So what does one do when you get a brand new (to you) gun that comes with a single magazine?
A. Start the search for additional magazines.

I bid on an Erma .22LR missing it's extractor …
after checking and finding a source for a replacement extractor.

OK, get the gun, get the extractor and fit it (with a little help from Ithacaartist)
Reading on another forum I get a chamber reamer and ream the chamber

I now have a nice little shooter, but still with 1 magazine.
I find and get 2 spare magazines.

They appear identical to the original but will only go into the mag well ¾ of the way
My micrometer shows the spine to be a smidgen (Tech term) wider.
I use a vice to compress the spine slightly, and yes it goes into the well a bit further,
but the mag base will not fit and will not compress.

I am thinking of dropping out the base(s) and reducing them but would appreciate any tips