help id suspected usgi parts

[remran44]

i need help iding what i think is a usgi barrel, it had a P proof mark next to what looks like a 8 under the barrel infront of the lugs, the left leg is marked with a sideways U. any ideas?

http://img410.imageshack.us/my.php?image=200803020107gd0.jpg
http://img228.imageshack.us/img228/3078/200803020108ax5.jpg

ive also got a two tone mag, any ideas what this is from? i found it tucked inside a 1918 colt.
http://img216.imageshack.us/img216/74/200803020133zn6.jpg
http://img23.imageshack.us/my.php?image=200803020134rb9.jpg

[Doran]

I don't recognize the barrel marks. The magazine looks Argentina with the wear patterns and the number but the font looks different. The magazine was originally full blue if Argentina.

[bgiven]

Barrel looks to be a commercial replacement, and the mag is someone's poor attempt to make a full blued Argentine pinned base magazine something it's not......