M1 Carbine Dilemma

[Full Clip]

I recently picked up a former CMP carbine off Gunbroker and then two 10-round magazines.
The look like they should just snap in, but the back of the mag at the top doesn't clear, preventing the dimples in the backside of the mag from engaging with the mag release mechanism.
The mags are just marked MADE IN THE USA. Could these be non-mil-spec mags for the Universal M1? Do they "look" basically the same but are not interchangable with the GI rifle?
Help!

 

[Omnivore]

They should fit straight up into the rifle pretty easily, the only resistance being from the mag-catch spring, and if the mag is loaded, from the follower spring. They then should drop right out when the release is pressed. If this isn't happening, try some G.I. mags (if your state hasn't banned tham). We have one 15 round mag out of about 10 here that fits too tight. All the other 15 rounders here are great. We don't use 10 round mags, but your state may have restrictions on the 15 rounders. The G.I. mags come in 15 round capacity only, and very, very rarely you will find one in 30 rounds. Most of the 30s are aftermarket, or so is the word on the street.

 

[SigfanUSAF]

Don't put too much thought into it, trash 'em and buy some USGI mags.

The mags are just marked MADE IN THE USA

 

[U.S.SFC_RET]

Before you trash the magazines make sure that the magazine release returns back to its original position. The spring could have rusted or rust in the assembly IMHO.

 

[Dave Markowitz]

10 round mags are not GI. Unfortunately, being in CA you may have problems acquiring GI 15 rounders, but they are the most reliable M1 mags.

 

[Full Clip]

Appreciate the replies. Fortunately, I have a 30-rounder that my father gave me years ago, so it's CA legal.