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Old December 31, 2018, 10:44 AM   #1
BigMikey76
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My AR Hates Southpaws

I am completely baffled. I took my new AR out for the first time last weekend. It shot fine for me, but when my buddy shot it, it would not feed the next round from the magazine. This happened with every shot for him, effectively making it like a bolt of lever gun, since he had to manually charge it every time. It never did that to me, though.

Yesterday, I took my wife to the range, and the same thing happened to her. Just as before, it shot fine for me.

What do they have in common? They are both left handed. My wife came up with the theory that there is something about lefties that the gun doesn't like, so she switched to shooting right handed. It ran just fine for her, until she switched back to shooting lefty.

Then I tried shooting left handed. I had to charge it manually on every shot. Back to righty- back to smooth proper function.

I am absolutely baffled.
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Old December 31, 2018, 11:48 AM   #2
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Did it even extract and eject the spent brass?

-TL

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Old December 31, 2018, 12:31 PM   #3
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That's really weird. I'm not sure what would cause this to happen. I'm left handed and have never had an issue getting AR's to cycle.
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Old December 31, 2018, 12:46 PM   #4
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Rifles don't know or care lefty or righty so you need to look at something else.
Need more info on the EXACT symptoms. The fired case is ejected? Did you try firing a single round with empty mag in place to see if there's a "short stroking" problem?
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Old December 31, 2018, 12:54 PM   #5
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If the problem is truly caused by shooting it left-handed, the only thing I can think of is that the gas block is loose and somehow it’s only being misaligned from the gas port when the hand guard is gripped by the right hand.
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Old December 31, 2018, 01:32 PM   #6
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Free-recoiling with a lazy grip, plus the added padding of winter clothing.
-The rifle equivalent of limp-wristing.

Try again, with them pulling the stock tight into their shoulder(s).
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Old December 31, 2018, 06:05 PM   #7
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Quote:
Originally Posted by FrankenMauser View Post
Free-recoiling with a lazy grip, plus the added padding of winter clothing.
-The rifle equivalent of limp-wristing.

Try again, with them pulling the stock tight into their shoulder(s).
It's virtually impossible to "limp-wrist" an AR-15. With a properly-tuned rifle, it won't matter how you hold it; the weight of the rifle and the gas operation will make sure it still functions even if it's not held against your shoulder. (That Vietnam War video of soldiers holding their rifles over their heads and shooting full-auto over a wall comes to mind.)

However, allowing the rifle to move rearward too much under recoil with an improper hold would -- in theory -- still make a tiny difference in bolt carrier speed. I suppose if the rifle was just barely functioning and was just a hair's breadth away from not having enough gas pressure to work the action, holding the rifle improperly might be just enough to push it over the edge and cause a stoppage. But that only means the problem was that the rifle was improperly gassed to begin with.
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Old December 31, 2018, 09:27 PM   #8
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Exact symptoms:
The chambered round fired, and the brass extracted properly. The next round failed to feed from the mag, leaving an empty chamber.
It is possible my wife was not holding the rifle tight enough, but I'm pretty certain I was, and I know my buddy was, as he is an experienced shooter, and has never had such an issue with any of his ARs, 2 of which were with us that day, and ran just fine when shot with either hand.
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Old January 1, 2019, 02:03 AM   #9
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Quote:
It's virtually impossible to "limp-wrist" an AR-15.
Try it with a new AR that hasn't been broken-in, hasn't been cleaned and lubed, and hasn't been proven reliable yet.
You may quickly discover that "virtually impossible" is actually "highly probable"...


Quote:
It is possible my wife was not holding the rifle tight enough, but I'm pretty certain I was, and I know my buddy was, as he is an experienced shooter, and has never had such an issue with any of his ARs, 2 of which were with us that day, and ran just fine when shot with either hand.
Humor me (and yourself). Give it a shot.
Try it yourself, even.

Hold that thing as loosely as you can, and give it a go.
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Old January 1, 2019, 07:42 AM   #10
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"The next round failed to feed from the mag, leaving an empty chamber."
Sounds like extreme short stroking. Even moderate short stroke leave the bolt wedged on the middle of the case coming out of the magazine.
Clean everything. Lube the cam pin with grease and a tiny bit on each lug of the bolt. A couple drops of oil on the gas rings. Hand work the bolt 40-50 cycles. This may solve the problem.
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Old January 1, 2019, 11:52 AM   #11
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Quote:
"The next round failed to feed from the mag, leaving an empty chamber."
Did the bolt go home on an empty chamber (it went over the top of the magazine before a round could be pushedup to feed)? Or did the bolt try to grab the next round and run out of juice (bolt is back, empty chamber)?
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Old January 1, 2019, 12:04 PM   #12
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Yeah, I agree with the others. Something else is wrong. Maybes are a plenty. Loose buffer (or cheap and flexing) tube, loose handguard, loose gas block.
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Old January 1, 2019, 12:09 PM   #13
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Are you possibly 'just barely ejecting' the shells, not fully compressing the spring?

If you've not changed anything on the AR between shooters, then it's the shooter or shooter's interface to the gun.
You could also have a gas block that is marginal, loose or blocked, but works for you. You might have a firmer grip that makes a weak gas block less an issue.

Have you tried a hotter load? That might help indicate an issue if there's no charging problem with the leftys and a hotter load.
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Old January 1, 2019, 12:43 PM   #14
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Quote:
Did the bolt go home on an empty chamber (it went over the top of the magazine before a round could be pushedup to feed)? Or did the bolt try to grab the next round and run out of juice (bolt is back, empty chamber)?
The bolt came forward, but did not grab the next round from the magazine.
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Old January 1, 2019, 03:05 PM   #15
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Any chance you are all using your offhand to grab the magazine well?
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Old January 1, 2019, 04:41 PM   #16
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No grip on the mag well. All shooters shooting thumb over bore.
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Old January 2, 2019, 10:48 AM   #17
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What kind of ammo are you using?
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Old January 2, 2019, 08:02 PM   #18
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Ammo was WWB 55gr. 5.56
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Old January 2, 2019, 09:57 PM   #19
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Quote:
Originally Posted by FrankenMauser View Post
Try it with a new AR that hasn't been broken-in, hasn't been cleaned and lubed, and hasn't been proven reliable yet.
You may quickly discover that "virtually impossible" is actually "highly probable"...
Sure, but you're talking about an AR that is already on the cusp of not functioning. In that case, the tiny effect of "limp wristing" it could nudge it over the edge of functionality.

But with a properly-functioning and properly maintained rifle, the effect of limp-wristing it won't be anywhere near enough to cause a stoppage. Which is why you can hold an AR-15 completely off your shoulder and still have it function just fine.

My point here is that if you’re able to cause a stoppage with your AR because you’re not holding it tightly to your shoulder, the ultimate problem isn’t that you weren’t holding the rifle properly, the real problem is that your rifle was already barely functioning to begin with.
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Last edited by Theohazard; January 2, 2019 at 10:12 PM.
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Old January 3, 2019, 08:12 AM   #20
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"My point here is that if you’re able to cause a stoppage with your AR because you’re not holding it tightly to your shoulder, the ultimate problem isn’t that you weren’t holding the rifle properly, the real problem is that your rifle was already barely functioning to begin with."

^^^that
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Old January 3, 2019, 10:49 PM   #21
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magazines

Any chance that those shooting left handed are using different mags than the guys shooting right (handed)?
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Old January 4, 2019, 09:27 PM   #22
BigMikey76
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I only have 2 mags (30 round pmags, both brand new). Tried both mags with all shooters. Both mags followed the same pattern - fine for righty, not so much for lefty.
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Old January 5, 2019, 04:55 AM   #23
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I can get either of my FALs to do that if the gas is set too low.
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Old January 5, 2019, 10:47 AM   #24
Bartholomew Roberts
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I’m inclined to agree with FrankenMauser and Theohazard that you have a marginally functioning rifle that is being “limp-wristed” when shot lefty. It is very difficult to do with an AR (I used to put the butt stock against my face to calm new shooters worried about recoil - pro-tip, don’t do that with a sharply checkered stock - it hurts and does not calm them); but I have seen it done.

Some diagnostic questions:
1) What does extracted brass look like? Any bites on the rim or popped primers?
2) Is the gas key secure?
3) What length is the carbine buffer spring and source?
4) What type of buffer?
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Old January 5, 2019, 11:10 AM   #25
BigMikey76
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Quote:
1) What does extracted brass look like? Any bites on the rim or popped primers?
2) Is the gas key secure?
3) What length is the carbine buffer spring and source?
4) What type of buffer?
I can answer #1 - the brass looks normal, so far as I can tell.
For the rest, I'll have to get together with my buddy ( he built all of his ARs from scratch, and knows a lot more about them than me).
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