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pt217

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Howdy all. Picked up my first AR a couple months ago and made one range trip so far. The gun is a new S&W M&P-15.

From what I can tell, depending on the number of rounds in the magazine, you may have a round that runs against the left feedlip or the right. When the cartridge is against the right feedlip, something weird happens. If the bolt is forward and I install a mag, then cycle the bolt to load a cartridge, the cartridge will get pulled from the lip with the rearward motion of the bolt (pointing upwards out of the mag). Then when the bolt comes forward the boltface rams into the side of the cartridge and jams.

Am I doing something wrong? I can't seem to find any info on this online. I should be able to load a mag under a closed bolt and manually cycle the bolt (pull back and release) and have it load a cartridge correct?

Thanks for all advice!
 
Is it only when the magazine is loaded to full capacity or does it happen every time you load a magazine with the first cartridge against the right feed lip? When the magazine is loaded to capacity how hard is it to seat in the rifle on a closed bolt?

A stated try a different magazine. If it is only occurring on a fully loaded magazine and it is hard to load when fully loaded it could be that your magazine has no play in it. I had problems with LAR magazines in my AR. I trimmed the legs on the magazine follower which gave a little more give when the magazine was loaded and the magazine Spring could compress when the first round was pushed against the bolt carrier.
 
Most AR feed issues tend to come from incompatible or poorly made magazines. The M&P 15 is an excellent AR known for quality, so it's likely that it's just the magazine like others have said.
 
vultr said:
Specifically I'd try a different brand. I tend to run Pmags in firearms that are fussy about mags. In my experience they have been the most reliable. It may take some trial and error before you figure out what works
Click to expand...

+1 on Pmags.

The feedlips on metal mags can bend (if that's what you're using) and it pulls the mag out of spec. I like running Pmags when I have issues because you know the lips aren't a variable, so then it has to be something else. (Unless they are really old mags...)
 
Thanks for all the answers. Sounds like what I'm doing should work in normal circumstances. To try to answer the questions:

Mags are both a brand new S&W 5rd and a brand new LAR mag (both do it if I recall, but I'll double check). FWIW they both seem IDENTICAL (probably the same factory).

Haven't tried at full cap, but I can do it repeatedly with only 2 rounds (only have 2 snap caps). If I remember correctly, with live ammunition it also occasionally failed to feed when I loaded the mag under a closed bolt.

It does seem more difficult to seat the mag under a closed bolt. Needs a little more force and seems to "snap" in differently
 
If you can borrow a different brand mag and see if that helps, I prefer steel mags over plastic if I have a choice. Its a long shot but also try a different brand of ammo, sometimes that will do the trick.
 
Another thing is perhaps the gun is still a little tight from being brand new, after they wear in sometimes they will run like a well oiled machine.
 
vultr said:
Specifically I'd try a different brand. I tend to run Pmags in firearms that are fussy about mags. In my experience they have been the most reliable. It may take some trial and error before you figure out what works
Click to expand...
Try to find out if one of your Pals are using one and check it out at the range..
 
Magellann said:
Another thing is perhaps the gun is still a little tight from being brand new, after they wear in sometimes they will run like a well oiled machine.
Click to expand...

Speaking of well oiled, make sure yours is. AR's like to run wet. If the BCG seems a bit on the dry side, add a quart, especially if it is new.

Auggie D.
 
Really stupid question. When you use the charging the handle to pull the bolt back; are you coming all the way back and then releasing it like a sling shot and letting it slam forward on it's own or are you assisting it into battery?
 
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