Help with new Build Issue

**GOST** · 18 June 2017, 20:53

Have you had a chance to try that upper on a different lower yet? Outta spec lower could have the BCG riding on either the hammer or mag. I've never had this issue but have read of similar experiences. One was an outta spec lower, another was an outta spec charging handle that was to tall. Hope you get it figured out.

**tappedandtagged** · 18 June 2017, 21:14

Originally Posted by GOST

Have you had a chance to try that upper on a different lower yet? Outta spec lower could have the BCG riding on either the hammer or mag. I've never had this issue but have read of similar experiences. One was an outta spec lower, another was an outta spec charging handle that was to tall. Hope you get it figured out.

I did try it with another upper. No issues. Likewise, the "problem " upper on another lower had no issues.

I need to get back to the range with all three of my rifles and swap parts around till something works.

Also, as for the lube, when freshly lubed (heavily) it would run a tad better (~15% failure rate vs ~20%). All stats approximate.

**GOST** · 18 June 2017, 21:35

Looks like in your pics that a lug is showing some wear, maybe from rubbing the mag. I'm grasping at straws though, I'm a poor gunsmith.

**cjd3** · 18 June 2017, 23:25

So I had a problem once with an out of spec upper. Does the carrier slide freely, with or without the bolt?

**tappedandtagged** · 19 June 2017, 13:57

Originally Posted by GOST

Looks like in your pics that a lug is showing some wear, maybe from rubbing the mag. I'm grasping at straws though, I'm a poor gunsmith.

I'll look at that closer. I haven't noticed any unusual wear.

Originally Posted by cjd3

So I had a problem once with an out of spec upper. Does the carrier slide freely, with or without the bolt?

Carrier slides/glides as it should without a loaded mag in place.

**tappedandtagged** · 19 June 2017, 14:12

I dredged up some video from back when I was actually doing the testing of the build. The rifle has actually been in my gunsafe for quite some time. Deer season, and then crappie season got me sidetracked. Now that its summer and the fishing has laid off, I'm back to my summer hobby of guns.

Anyway, here's the videos I took (if they upload right). The Brownells BCG has already been sent back and replaced with a Battle Arms BCG. Although the videos only show the use of the factory metal mag, I tested all the mags I have at my disposal in the similar manner. I also tested it with downloaded mags (20 or less) to see if that would make things go better. They didn't. Now that I watched the video, I'm second guessing myself as to whether I swapped the buffer/springs out.