m16 jammed

the m16 jammed during firing what is the first thing must i check or if there is a multiple of things to check can someone tell me in order. without pull'n down the weapon

There are certain things to look for. Put ALL ammo and magazines away. With an unloaded rifle, carefully inspect some critical parts. Your jamming can be occuring from short cycling, poor extraction or ejection. First check for binding in the bolt carrier. With the charging handle in place and the upper detached, slide the bolt carrier in and out without chambering any rounds. The carrier should slide in and out very freely without requiring much force. Bad carrier keys are common and have been known to cause binding that will cause a lot of wear on the upper and lead to jams. Make sure the buffer, spring and tube are properly lubed. The buffer tube should be smooth with no lathe turning ridges. With the rifle assembled, pull the charging handle back and note some force is required to cock the hammer. Then let the handle back and repeat. There will be some dragging of the carrier on the hammer, but it should not require much force. Try again with keeping the trigger pulled. This time the disconnector will keep the hammer pulled back even farther, so the dragging will be very light but still there. There may be a problem with the lower/hammer if too much drag exists. Bad ejector tension is a major stumbling block that can be very frustrating. Aftermarket bolts are frequently assembled using the same springs for the ejector as is used as a detent spring elsewhere on the rifle. The problem is that the ejectors themselves vary in length and possibly the holes in the bolts do too, so when these springs are used, they usually create excessive force on the ejector. The gun may appear to function properly but after a rapid fire string in the summer, cases will start jamming up into the gas tube groove in the upper receiver. When at the range, periodically check the angle and distance of your ejected brass. It can tell you a lot on how your rifle is functioning. A strong ejector tension will kick the brass out at about 5 o'clock 10-12 feet back. The rifle will mostly function OK until the spring heats up and loses tension. The brass will not kick out as far and then jams occur. Proper ejector tension can be achieved by cutting or grinding the spring so there is practically no tension when the ejector pin is installed. The brass will then typically kick out about 2-3 ft at 2-3 o'clock, and there will be no more jam problem. If rounds are sometimes not chambered it is due to the bolt not coming back all the way. This also causes jams since the case may not be ejected. If the rifle bolt is not cycling, make sure the gas port opening under the front sight, inside the barrel is not plugged. The problem is either something is binding or the gas system is leaking or plugged. Spray solvent down the gas tube. If its not running out of the barrel, its clogged. Push long pipe cleaners all the way back and forth until it comes out clean. The spray solvent in the tube again until it runs out of the gas port in the barrel. The gas tubes are supposed to be self cleaning and seldom plug up unless perhaps you are using light loads that produce a lot of carbon. It is important to know your gas system and where the possible leakage points are: near the front sight, at the carrier key, at the gas rings, and where the bolt extends through the carrier by the firing pin. There will typically be some leakage at the front sight as seen by some black deposits, but if the tube fits tight it is probably OK. The bolt post to carrier hole clearance is typically very tight. If the bolt does not fall out of the carrier when you invert it, the gas rings are probably OK. It is a good idea to separate the gaps each time you install the bolt anyway. The biggest source of gas leak trouble I have found is the carrier key to gas tube contact. There are a lot of bad carrier keys out there. This is the one item that should be looked at very carefully. Not only are they a source of potential bolt/carrier binding, but they can cause excessive gas leakage if the fit to the gas tube is bad. Gas tubes have a little ridge on them where they fit into the carrier key that determines the degree of gas leak sealing. The ridge can wear down a couple mils which then can cause excessive leakage. That can happen after as few as 1000 rounds with some rifles depending ton the ammo fired. The quality of the carrier key can definitely affect this and cause the gas tube to wear and excessive gas leak problem. The key should be uniform, symmetric, and had a nice smooth inside surface that made a good fit to the gas tube. If we call 1.464 0 headspace, then the others are at +3, +6, and +10 respectively. Typically the headspace on a rifle will be around +3 to +5-6 or so and they will be fine. Another point is that the armorer gages are machined down on the edges of the base so no contact is made with the ejector so no tension will be applied due to this when the bolt is closed. The proper way to operate the gage is to load it in the chamber and let the bolt/carrier drop slowly into position under its own weight and not to push it down under pressure. If the bolt does not close all the way, then you know the headspace is below that of the gage. Good luck.

"When Determined To Survive, Leave Nothing To Chance"

Your welcome. Please let us know if the rifle gives you any more trouble.
"When Determined To Survive, Leave Nothing To Chance"

Whats funny that mine did something I laughed at and yet close to beeing danger zone. I go out and shoot for fun and testing if it can operate in the winter and one of the bullets got stuck near the barrel and the front end went in the inside towards the powder and yeah nearly hit the bolt and yeah always clean your rifle and look at the ammo.

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