This carbine has a type 2, unmarked recoil plate. With action out of the stock, I checked the fit on the tang and sure enough as expected there is substantial play.
I checked my midway NPM...it has a type 3 inland recoil plate that fits good, no play but not snug either. I tested it on the African carbine and...nice-n-snug fit. Presses on with a just a little thumb pressure. I added 4 layers of business card to the front of of the trigger gaurd, and everything slid in a little snug, but not tight. It's range ready now. If all goes well, I'll slather some grease on my business card spacer. Posterity can read my name on it.
So, that type 2 plate was loose on the NPM as well. I pressed it slowly in my vice between aluminum blocks to tighten it up, checking progress with a micrometer. After 3 iterations of of this, I had about half the slop out of it, but was still pretty loose. As I pressed it once more...you guessed it - snap. It was just too loose to correct.
Type 3 recoil plate is on the way to make all well.
I'll switch over to getting the matching 1942 underwood typewriter working again. Is anyone interested in seeing that? I think I have its problems figured out. It freezes up and won't advance after 3-5 key presses.