My shooter upper. Thanks GT!!!
 

My special thanks goes to GT- he did a great job fitting a nice Mauser toggle for my upper slide/ barrel he recognized as a ww2 Mauser armorers kit. He went above and beyond, replacing with his own my mismatched and misfit modern ejector and main pin.
Today I have tried this upper on my 1977 Interarms lower.
The side plate from 1977 doesn,t fit as you can see on the pictures- 1977 doesn,t have a ridge above the sear.

And p08 Sarco remake I also had to modify for perfect fit. I will clean and blue the grounded surfaces later.
The result is - an excellent shooter.

Now I will leave the 1977 upper alone with “low mileage” , having shot through it perhaps only 3-4 mags.

Again, GT, YOU ARE THE MAN!

Just reblued the side plate.
 

Perhaps rougher inside, I think the grip cut out came out pretty decent with the fresh blue.

Sarco didn’t,t polish the plate, looks like a cast. Actually fits quite well with some portions of my modern Interarms lower also looking like rough cast.
All the adjustments on the plate are working very well, it locks into position and sits tight not imposing on trigger and slide movements.