I have a Colt Mustang Pocketlite 380 and it fails to chamber or jams pretty consistently. Only fires without problems with only 3 rounds or less in the mag. I believe I heard this is a common problem and could be the magazine design or something? Would like to get it functioning properly. Never shot very much. Also, what would one of these be worth? Its near mint I think, probably less than 200 rounds.

I have a Pocketlite, and I have never had any problems with "jamming."

You need to be more specific, is the gun "jamming" on the eject or on the feed?

Have you tried other ammo brands?

When did you last clean it?

Limp wristing?

The Mustangs might not be the most accurate pitols but they are pretty reliable and what your describing is not at all common.  Have you tried another magazine?  What ammo?

Its actually been awhile since i shot it so ill have to shoot it again to see exactly what is happening. I'm pretty sure it fails to chamber a new round after it ejects the spent. Winchester white box fmj ammo. Its clean. Maybe it just needs some more lubrication or different ammo or something. When pulling back and releasing the slide it almost feels weak and like it barely has enough power to chamber a round.

Try a stiffer Recoil spring from Wolff. You can also try a Sig P238 magazine since I know Mustang mags fit in the Sig P238 so I would think the Sig mags would fit in a Mustang.

I mention this since Sig copied the Mustang including the springs and mag followers. Recently they updated the mag followers (slope with dimple) and recoil springs (stiffer) since there where similar failures people had with the Mustangs.

I would thoroughly clean & lubricate and try it again. I would try with another brand of ammo, and a different mag. The original gun had an inner/outer recoil spring, are both springs in place?

When cleaning gun be careful not to push the ejector too far down the mag well, otherwise you will have to depress the mainspring in order to reset it. This little "feature" sets it apart from the 1911s.

OK I lubricated the gun today and i tried chambering rounds and found that the ammo i currently have for it is flat point fmj rather than round nose fmj. This edge was catching the front of the mag where it pops up over into the chamber and catching the round or dramatically slowing it down. I did a quick fine polishing job on that little bevel on the mag and lubed the gun up well. It then proceeded to function flawlessly for the few clips i put through it. I believe the ammo is most of the problem, and with some round nose ammo the problems should go away for good. If they come back, I believe i will look into upgraded mags as mentioned, as it seems the angle isn't quite right and the rounds dont sit evenly or angled enough in the mag.

Don't mess with the feed ramp until ALL of other possibilities are eliminated. Try different mags and ammo combos. My gun functions flawlessly from the factory with RN bullets.