[Tegboarder]

On Gas - The whole "gas-operated" term has gotten thrown around a couple of times and it's important to clarify that gas systems cover a wide spectrum of operations (gas direct, gas tappet, gas blast). There's nothing necessarily wrong with gas direct systems but the M4 just doesn't have any way to remedy sluggish firing without cleaning out the gas tube. Just as an example, the M240 has a gas regulator that can be adjusted to allow more gas to engage the rod assembly which gives more power to the whole operation of the system. It's a quick fix for which will hold you over until you have the time to remedy the situation 100%. It'd be a great if there was a gas regulator on the M4 that could be quickly adjusted when it starts to get sluggish from carbon build-up.

Back to the .223/5.56 - The lower receiver is stamped with all the manufacturing information to include what the barrel that particular lower came out of the factory mounted to. If it's stamped .223 then it was made to only fire the .223 Remington and firing the hotter burning 5.56 will damage it. If it's stamped 5.56 it will fire both since it's made to handle that hotter burn.

Magazines - The issue magazines are "semi-disposable". Cheap enough to be easily replaceable so that damaged ones could be turned in for new ones without much fuss. The problem is we expect them to last forever. Compare that to the AK-47 mags which are actually made to last a lifetime. Country of origin can tell you a lot about a weapon. On one hand you have the U.S. who weren't worried about spending the extra money to replace something as simple as magazines. On the other hand you have the USSR who would sooner make a more reliable magazine that didn't have to be replaced over and over again in order to save money in the long run.

Misfeeds - The extractor could be failing, leaving the spent round in the chamber and preventing another round from being chambered. There was an issue with the extractor spring on early M4/M16s. It was replaced with the little black donut on later models and the early ones were sent in for the fix.

Magazines and Misfeeds - If you're not getting any misfeeds when the magazine is full but start getting misfeeds toward the end of the magazine it's probably the spring. A full magazine is going to have more tension in the spring compared to a half magazine. There could also be an issue with the follower. It may be beat up and catching inside the magazine which will result in a misfeed. There can also be problems with the lips of the magazine. If the lips are bent or damaged then rounds aren't going to feed properly.

Maintain your magazines and you'll be fine. Stretch out the spring a bit to keep it from "memorizing" it's compressed shape and losing it's tension. Compare the lips of all your magazines and look for inconsistencies. Or if you can afford it just buy plastic magazines. They're durable, light, and the internals are made better as well.

For Soak60 - As far as shoving your fingers into places and diddling around there is only one place that is necessary and it's not your magazine well. If you have to do remedial action then just flip your weapon on its side and LOOK through the ejection port into the chamber. Then you can start fixing it however you need to. If it's something that needs more than a shake and a slap just use a leatherman. Your fingers will thank you.

The "click" - That click is from the disconnector reengaging. Yes, it means you can "pull the trigger again" but listening for that click shouldn't affect the pressure you're applying to the trigger. Unlike the M9, every squeeze of the trigger is the same on the M4. The first shot doesn't set the hammer (like with the M9), charging the weapon does.

Rambling complete.