New AR build, a couple issues.

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.Scarecrow.

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So I have roughly 600 through my new AR build. At the 500 round mark I experienced 1 double feed. Between 500 and 600 rounds I experienced 2-3 failures to lock back on an empty magazine.

I believe all these issues happened with the same magazine, I know for a fact that 2 of the failures to lock back were on said magazine, (Gen 2 PMAG).

A little info for those interested

Rainier upper and lower
Griffin Armament BCG
Sionics Barrel, Mid-Length 16
H2 Buffer

First 350 rounds or so I used FrogLube
Last half I used Coastal Lithium Wheel Bearing Grease

Do any of these malfunctions sound odd or concerning? I just want to take measures to make them not happen again (Within reason, no gun is perfect) if possible.

There may not be an easy answer but I'll take any help, thanks guy.
 
1. don't use grease
2. don't use grease
3. make a scratch or something on the mag, and if it happens again after you go back to frog lube or any other oil, then ditch that mag
 
The double feed points to a bad magazine. Trash the mag and use another.

Failure to lock back might be mag related (follower not engaging the bolt stop) or it could be that the gun is short cycling. I'd replace the mag and see if that fixes it. If you still get failures to lock back, I'd Use a lighter buffer and see how that works.

I've used grease and never had any problems.
 
Bad mag was my first thought, too. Mark it and run more through it, see if you can duplicate the failure. If you can, set it aside and try to duplicate with another mag.

I'm not a fan of the BAD lever (pretty pointless for a long fingered lefty), but unless you're actuating the bolt release inadvertently, I doubt that's the problem, and wouldn't account for the double feeds.

Grease... could be the higher viscosity is actually slowing the bolt travel. Slower bolt travel can short cycle. Short cycle won't lock open the bolt. I haven't seen a short cycle cause a double feed, though. A non-feed, sure. Maybe a bullet over bolt :yikes: But not a double feed. Not saying it impossible, just that I personally haven't seen it.

Clean the gun, oil it, and test that mag. Or replace the spring. Check the follower for dings, dents or any other malformations. Could be as simple as replacing a follower or spring in an otherwise good mag.
 
Go back to square one and troubleshoot from there, might be tolerance stacking. Remove the BAD lever, install a carbine buffer, clean/lube w/oil and test again. The BAD lever can cause failure to lock back due to the extra weight on the bolt release paddle, some midlengths don't like heavier buffers.
HTH...
Tomac
 
As others have said...most likely magazine related. I would send it back to magpul. I would bet that they would send a new one to keep a customer happy.

I would also check the gas key to make sure it is properly staked and has not loosened. If not, you may have to get back to the basics to find the problem. Degrease/clean, relube and remove aftermarket products that directly affect cycling/bolt. Test fire, then start adding components again until it starts to fail.

Also, grease is great for an M14/M1a. Not so great for an M16/AR15.
 
i agree MOST ar15 malfunctions are due to bad mags, but my bet based on the symptoms as described is still improper lube
 
You cannot assume that all gun oils and greases are compatible. Using the wrong mix can gum up. Grease generally holds grit and crud in while oil flushes it.
 
Many will mistake an empty case and a live round jammed in the action a "double feed. It is not. A Double Feed is when the mag releases two live rounds into the action. It is strictly a magazine problem.

When an empty case and a live round get jammed in the action, it's usually the result of a malfunctioning extractor
 
I use lithium grease, but only on the charging handle. The bolt, carrier, etc. get oiled. But I agree with the magazine opinion. Segregate the mag and go from there.
 
mist, exactly. and that malf happens WAY more often than an actual doublefeed, but everyone still calls it that, so i just assume that's what they mean these days.
 
Scarecrow,
Simply put, tolerance stacking is when two or more components that, although within acceptable tolerance levels individually, work together in such a way as to exceed acceptable tolerances in one or more areas.

In your case, for example, your rifle might work fine with the BAD lever, the heavier buffer or the grease, but using them all together might be causing your malfunction so hence my suggestion to remove both the heavier buffer/BAD lever, lube w/std oil and begin testing from a point of known reliability.
Tomac
 
M193 is plenty stout to run the gun efficiently, but many things can still hamper proper operation:

Number all your magazines. Keep track of what mag the malfunction occurs with.
Ditch the BAD lever and froglube veggie oil. Froglube can congeal after sitting a while. Use a dino-based gun oil or motor oil.
Step back to a carbine or H1 buffer.
If you are having extraction issues, ensure the chamber is clean and install a stiffer spring and o-ring on the extractor.
 
I number all of my magazines. If I get repeated mag induced malfunctions in one I get rid of it. The ban has been gone for 11 years. There is no need to hang on to magazines and rebuild them, or try to bend worn feed lips back into spec.

I second taliv in saying don't use grease. I use military issue CLP (simply because I have a lot of it) or Slip 2000. From your description I'd say that you are experiencing short recoil instead of a double feed.

Clean the grease out of it and relube with Froglube and see if that fixes the problem.

As others have said, I wouldn't run an H2 buffer with a mid length gas system. I would try a standard carbine buffer first.
 
out of curiosity, did you start with frog lube and then just start throwing grease on top of it? or did you thoroughly clean off the frog lube before applying the grease?
 
I use syn bearing grease applied sparingly. Nickel boron bcg. Rifle runs like a swiss watch.
 
It was a legitimate double feed, 2 live rounds were trying to go in the chamber. It was NOT a failure to extract and a live round behind it, I should make that clear.

I also swapped out the H2 for an H I had lying around.
 
Got a feeling it wasn't a true double.

Check your lube, clean your extractor, try a different mag, check for gas leakage around the gas tube. If the BAd lever makes a difference, replace your bolt catch and spring.
 
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