HELP -- USGI 30rd M1 Carbine Mag's

[JimF4M1s (Deceased)]

$15 more from what starting point. Though if your only buying one I would take the hardback.
If the price was right I'd get #1, #2, and #4.
I've had poor reliability with some J mags. Because I have many of the others I shy away from them. I know others who have been happy with the J mags.

And I think you did OK on the carbine at $600. Make sure it has the late mag catch if your getting the 30 rounders. If not they are a low cost item, even the marked ones.