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HeruMew
05-10-18, 15:32
16” Mid-Length 5.56

https://image.ibb.co/mkA6iy/S0552180.jpg

I started out this build with trying to fill out the last Anderson lower I have. Using that as my base, I went a bit more quality driven on most of the components.

Starting off with a BCM upper, this “Stripped” upper actually came assembled and had a big scratch on the non-port side. It bugged me at first, but the forward assist and port door was installed. It was obviously assembled, but I am thinking that this was built out by BCM, for either Demo Purpose or it was going to be on one of their full rifles, and the finish got scratch too much for them to use.

Either way, it works fine for me, I used to cover it up, and I think it looks fantastic anyways. This one will probably get painted to Minnesota Late Summer Foliage, so I am not worried about surface aesthetics.

Mounted a Bear Creek Arsenal (Guaranteed 1 MOA @ 100 yards and will be putting that to the test very soon, will make sure to update with targets. My home range is still down while I get my crap together and get it rebuilt.) 5.56 NATO barrel with a 1x7 twist. Gas port gauges in at a perfect .072; I tried to do as much research as I could on this one before jumping. It, of course, has the FSB which is required in my mind.

Just got in the PKMR, that was holding up the finishing of the build as I didn't have anything for Mid-Length. When I received it today, I panicked for a moment as it says it only fits a triangle handguard cap...

I can say, that it seems to fit the round handguard cap just fine... So, I am worried, as it either shouldn't have installed so easily, or something isn't lining up as it's supposed to. Should I even be worried about this? Their website makes the same claim, and you can buy an insert (though I can't find it), but it doesn't look kitty wompus, nor does it wiggle or anything of the like. Hopefully we can get some input on if this is even an issue anymore?

https://image.ibb.co/mcBOVd/S0492171.jpg

Upper:
Stripped BCM Upper w/ Dust Cover and Forward Assist
Bear Creek Arsenal 16” 5.56 Mid-Length w/ FSB; .072 Gasport
Spikes Tactical Melonited Mid-Length GasTube
Toolcraft C158 BCG w/ Assembled Bolt
BCM PKMR Mid-Length Handguard w/ Grip
Magpul MBUS (Temporary for testing)

Lower:
Anderson Lower
BCM Lower Parts Kit (For everything that wasn't swapped out for other parts)
Extended Takedown Pins (cheapies I wanted to test out, not sure I will keep them if they catch on stuff)
ALG-QMS (Best trigger I have ever used, hands down. I love it, and will be picking up more for the cost.)
JoeBobOutfitters Ambi-Safety (Had one Ambi safety from PSA and hated it due to the bump hitting my trigger finger. Loved the way this one looked, and the pricing was fair.)
PWS Ratcheting Castle Nut / End Plate (if anything will be swapped out, I have a feeling it will be these two pieces. We'll see how it holds up.)
VLTOR 6 Position A5 Tube / A5-1 Buffer (Going to try a 0 and 1. I those don't satisfy me, I will have to switch to an A5-2)
Ahem.... an A2 Grip
MFT Minimalist Stock (I will be switching this out to a Magpul ACS-L when it arrives. I got too antsy and slapped this on to test fire and finish out my build.)

Overall, this build, in my plans, to run this Sum-B HARD.

It's smelt time, but I have a class scheduled for June and I will be using this rifle. Plan to put it through it's paces, better myself, and see how I like he midlength gas system.

https://image.ibb.co/dKBqAd/S0532175.jpg

I just hope I did the right research and got everything lined up (in regards to consistent LRBHO and the like) for longterm operation. It will be very interesting to see how it all goes. This will be the very first non Carbine Gas system rifle I have owned.

Nonetheless, if I missed anything here, feel free to point it out, I can always edit it up and adjust. I don't believe I have missed anything besides getting some target pictures up here as well.

https://image.ibb.co/cf5TwJ/S0522174.jpg
https://image.ibb.co/b1tgGJ/S0482169.jpg
https://image.ibb.co/jp2abJ/S0502172.jpg

I will be going out right after hitting submit and putting a couple hundred through it.

Also, I thought these pictures did half alright.

HeruMew
05-10-18, 16:07
First 200 had a few stoppages, the ejector is sticking. I was running an H3 this time, will try a lighter buffer tomorrow and see if it alleviates. I send the BCG home and it snaps back to proper position, but after somemore it double feeds again as it doesn't kick the casing. It feels amazing with the H3. And locks open on last round. Only did a few mags though, so will try again soon.

pubb
05-10-18, 19:19
I think H3 is a little heavy for mid length.

HeruMew
05-10-18, 20:48
I think H3 is a little heavy for mid length.

I've never heard of a heavy buffer impacting the ejector. But, I don't have a lot of anecdotal evidence for that.

It would double feed with the casing sticking straight forward, towards the chamber, and wouldn't eject it no matter how hard I cycled it back.

When I was done fishing this afternoon I pulled the BCG, disassembled the BCG, and checked it all over. The ejector was stuck at about the 1/3 mark.

When I spent 13 dollars on a bolt disassembly tool, I had hoped I never had to take it out of the bag. I took it out, depressed the ejector, and let it go. It sprung out. I added a couple drops of Slip2k, used an empty casing, and pumped the ejector about 100 times. I felt the grittyness start to leave. I repeated oiling and cycling with the case and now its buttery smooth. It took about 3 cycles of adding some drops and cycling. About 300-400 pumps total.

Swapped out the A5-3 with the A5-1. It was getting to dusk and decided not to shoot more today, but I will run 100 more through it tomorrow. If it gives me more problems, I will call Armorally.

Either way, I think that was it. It came very dry, and I thought I lubed it pretty good, but, I did accidentally ignore the ejector, in my novice ignorance. It was pretty dry still before I applied lube and cycled it.

HeruMew
05-11-18, 15:45
Ran the A5-1 for about 100 rounds, the recoil impulse is nice. Not as nice as the 3, but quite nice still.

Ran 100 flawless rounds, no more sticky ejector. All extracting out evenly and nicely. Had nice pile of brass with just a couple weird fliers. Other than that, excited to keep slinging lead with this thing. It eats Lake City 62gr M855 wonderfully, shame I am down to my last 200 of this stuff I got.

Hammer_Man
05-11-18, 20:33
Looks like a pretty solid build! I'm curious to see how the Bear Creek barrel performs over time, please update this thread after your class this summer. In regards to buffer weight, I wouldn't run anything over an H2 in a 16" mid length, but YMMV.

HeruMew
05-13-18, 17:10
Looks like a pretty solid build! I'm curious to see how the Bear Creek barrel performs over time, please update this thread after your class this summer. In regards to buffer weight, I wouldn't run anything over an H2 in a 16" mid length, but YMMV.

I sure will update the couple custom build threads I have with Bear Creek Barrels. I have a lead sled and plan to see if the barrels hold up to their claims.

Nonetheless, it runs wells so far, and I hope it'll keep running for the 500 or so rounds for that class.