This is standard practice. Leaving magazines fully-loaded for long periods of time, especially aluminium-bodied magazines like these, causes the lips to bend out of shape from the upward force of the compressed spring. "Lip creep" leads to a really high rate of double-feed malfunctions. For this reason, the magazines are traditionally stored empty while the ammunition is stored on stripper clips, and the "spoon" adapter makes for very quick work of loading when you actually need to go to war.
Well, Magpul PMAGs are pretty awesome because they come with a snap-on dust cover that pushed the ammunition down, away from the lips, so you can leave them fully loaded indefinitely as long as the cover is on.
All USGI AR-15 magazine bodies are aluminium. The original, 20-round Colt Metalform magazines from the 1960's and early 70's have cast aluminium followers, don't know if yours does. There are no steel USGI bodies or followers.
Just trying to be informative, not a jerk... sorry if it comes off that way. :/
it is pretty much the same. some say the X stands for surplus overruns from normal M855 military ammo. chances are it is just marketing. i just put down what was on the box it came in. as for the M855A1, i did not find any for sale. but the idea behind it is the bullet is made out of all copper with a steal tip. so no lead in it.
Yes, I know about the M855A1; I ask just to find out the difference with that XM855, which I never heard about... From this [link], it appears that the new M855A1 is a Great Round, which will keep newer Calibers like the 6.5mm Grendel and the 6.8mm SPC still "at Range"!
It is hard to say if they will replace the 5.56 but I think they will not. It might not have the out right stopping power of the bigger rounds but it does some serious damage to the human body. If look around on the internet you can find a couple picture of what a 5.56 does to the body and it is pretty brutal.
Ah, OK now: I thought you were talking about the M855A1... Yes, I fully agree at the moment: the 5.56mm NATO, along with the 7.62mm NATO, will be used at least for the next 10-20 years! Both are very accurate, with the 5.56 being smaller, lighter, slightly faster and in some cases more penetrating; while the 7.62 retaining higher Stopping Power and longer Range! The 6.5 is very accurate as well, but rather larger compared to the 5.56; while the 6.8 having more Stopping Power than the 5.56, but less than the 7.62 and shorter Range than both the 5.56 and the 7.62... Am I correct?