While I'd certainly clean the gun and magazines ... making sure the magazines are clean and DRY, but the gun itself properly lubricated ... how experienced are you when it comes to shooting diminutive .45 pistols, and what ammunition are you using?
Dirty magazines, or magazines which contain residual goo from the factory shipping oil (which can congeal and make sludge), can contribute to feeding & chambering issues. If the "timing" of a round being fed into the chamber is "off" it can lead to stoppages, including failures-to-return-to-battery. (So can a dirty and improperly lubricated gun, at some point. You guess the point at which this may happen.)
Low power ammunition (and even over-powered ammunition) can contribute to this, as well, though. Slide travel and velocity during its travel/cycling.
Then there's the potential for a shooter grip issue to induce feeding issues. In particular, an unlocked wrist and "too relaxed" of a grip can sometimes cause this sort of thing to happen. An improperly supported pistol may experience issues when the slide velocity and travel (length of the slide's run to the rear) are affected by an unstable "grip technique". Or, put another way, a frame which is insufficiently supported by the stability of the shooter's grip can "rob" power from the recoil spring's ability to properly move the slide at the right velocity, and far enough in its rearward travel, to allow it to exhibit optimal feeding/chambering.
Then, there's the consideration that shortened .45's with reduced slide mass, shortened slide run and increased slide velocities are generally considered more sensitive to shooter & ammunition influences ... and more easily adversely affected by both ammunition and shooter grip influences ... compared to larger .45 platforms.
I was called to inspect a CS45 which was reported to be constantly experiencing feeding stoppages. Nothing appeared obviously wrong with the gun or mags, although the recoil and mag springs were becoming a bit light in tension. The gun ran just fine, though, even when used with some "low cost/contract" 230gr JHP loads ... in my hands. I had a couple of the other instructors try it and they had no problems, either ... until I instructed them to deliberately relax the firmness of their grip a bit, and "unlock" their wrists ... while I observed ... at which point they could make it experience a feeding stoppage, virtually "on demand".
I cleaned and lubricated the gun, and installed new springs (since I had some at that time), and told them to return the gun to the owner and discuss the importance of a solid, proper grip when shooting itty bitty .45's.
Now, on the other hand, I recently had a guy qualify with a CS45 he's owned for a little over 10 years. He's not what many folks on this forum might consider to be a "gun enthusiast", and he apparently doesn't take the time to do a lot of practice, but he's more interested in his abilities than the majority of cops I've seen and demonstrates pretty decent skills and ability.
His CS45 didn't miss a beat when he used it. I was talking to him afterward and learned that he hadn't replaced either the recoil or mag springs in his personally-owned CS45 since he'd bought it. (The factory recommendation is every 5 years or every 5,000 rounds, and I prefer to err on the conservative side of things when it comes to the littler guns with short recoil springs and faster cycling, myself.
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Apparently, his good grip and attention to utilizing proper shooting skills, as well as keeping the gun clean and lubricated, helped him avoid experiencing functioning issues even with his aging springs. (He was also shooting the issued 230gr JHP's, which are a "premium line" made by one of the major American ammo companies, and using good ammo doesn't hurt.) I strongly recommended he order new recoil & mag springs, which he promised to do.
Now, even a shooter who has a decent solid grip, and properly locks his/her wrist, can become fatigued when shooting ... and especially when shooting the harder recoiling little guns. If this occurs just enough to impair the quality and stability of the shooter's grip, it might be just enough to affect the cycling & functioning of the little .45's ... anybody's little .45 models.
The smaller the .45 model becomes, the more important it becomes to use good quality, fresh factory ammunition and pay attention to grip technique.
Oh yeah, and the "tightness" you feel in the "mag spring" is likely due to the extra set of indentations used in the CS45 mags, at the bottom/rear edge of the standard lip impressions on each side, which are needed to keep the top round from being displaced from the mag lips under the heavier recoil of the little gun. If you eventually determine that a specific mag is connected to the feeding issues (after examining and eliminating cleanliness, lubrication, ammo quality and shooter-related grip issues), I'd call the factory and ask for a new mag under warranty. It's not unknown to have a mag sometimes slip through which might offer less than desired feeding and functioning (or which might have suffered some sort of damage, especially if it's a used gun).
Just my thoughts. Obviously I can't be there to see you shoot the CS45 or examine the gun & mags, so I can't know what's involved in your particular case.
