I have one and it functions perfectly with Rem/UMC 115gr FMJ.
100's of rds w/ no failures. I do carry it and it's the only semiauto I do because of the fact I can easily operate the slide.
Not so with any other semi for me.,,just a fact of life for me now.
They are designed for FMJ ammo. That's what they work best with.
Stay away from anything +p. Most shooters just use a generic Winchester or Remington FMJ.
Mine is the non-reinforced frame (no hex-pin reinforcement just ahead of the trigger pivot) as yours is.
I started shooting mine to 'save' my two WW2 mfg Walthers from wear and possible damage.
Go over to the P38 forum:.
http://www.p38forum.com/
There's a section on Post War P38/P1 pistols. Lots of info on history, care, ammo, selection, values, etc.
$150 is an excellent deal. About half of what would be considered a great price in most places.
Mines never had a problem and I don't feel at a disadvantage or in some way 'under gunned' with it.
Excellent sights & trigger. Very accurate at 25m off hand. So much so that I could use it in a Bullseye match again I think at least on the indoor range and get respectable scores.
The bottom mag latch doesn't bother me as I grew up with a Ruger Standard Auto and plenty of fine Euro semi autos.
Magazines and extra parts are very available and inexpensive.
It works well, I shoot it well, I don't read the Tactical Magazines articles to know that it's impossible to use as a CCW.
Works for me.