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DMR 5.56 build, Finally finished it

B Man

Little Sergeant
Full Member
Minuteman
Dec 23, 2010
608
734
South side of Big River
I dove off into the AR world last year having a guy build me an AR308, then my wife a 5.56 both 20” barrels. Quickly saw I wanted me a 5.56 too. So I decided to do this one on my own, a lot of research on here and the web and here it is finished. I just did a function test and barrel break in today with some old bulk Thunder ammo 68gr bthp. Before leaving I put one on steel at 500 yards, adjusted and shot one group just to try it out. Can’t wait to see what it’ll do with some better ammo and start testing some handloads.

Build list

- [x] MEGA AR15 MML BILLET UPPER RECEIVER WITH 14" M-LOK HANDGUARD
- [x] MEGA AR15 BILLET GTR-3H AMBI LOWER RECEIVER
- [x] - Proof Stainless 20” 223 wylde
- [x] Badger Ordnance Condition One 34mm 20 moa Tan
- [x] Optic- Steiner T6Xi 2.5-15x50
- [x] Geissele Ultra duty LPK
- [x] - BCM mk2 Recoil mitigation buffer system T1
- [x] Geissele SD-E trigger
- [x] -Radian LT Ambi charging handle
- [x] -FAB gradus rubberized pistol grip
- [x] - Magpul PRS Lite
- [x] -BCM FDE bolt carrier group
- [x] -Superlative Arms Adjustable Bleed Off Gas Block
- [x] Aero melonite gas tube
- [x] Fab Spike bipod
- [x] Hyperfire Brake gen2
- [x] Cerakote by Nine Run Gun. Magpul Green/ Graphite black barrel/ Tan & Gold mix misc small parts.

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Well sir you and padom were the main two influencers in my decisions from researching on here. So I really appreciate the nod from you on it.
Thank you, there's a couple things I would change but it's definitely a solid well thought out build and your high level attention to detail is obvious.

A lot of people on here just seem to pour their money into the wrong areas of their builds, like buying a quality matched receiver set but a shit barrel.


You started with a solid receiver set that utilizes a unique design that increases accuracy over the traditional barrel nut to handguard design.

Picked a quality single point cut barrel at the perfect length for the smoothest operation, best barrel harmonics and optimal velocity.

Proven Two Stage Match Trigger, (throw a JP Yellow trigger spring kit on it you'll like it even more)

Choosing BCM for your operating parts was very smart as well, may not be the "smoothest" option but will definitely serve you well and not affect accuracy.

All other aspects are basically user preference but all solid choices.

Let us know how you like the Muzzle Brake, I've watched a couple videos on it but have no real world experience with the Hyperfire MB.
 
I regret not doing a small frame MML, I’ll say that as I look over at my matched Mega billet set with M89 rail last time I built a DMR. Maybe I’ll sell the upper and build a new one. 🤔

Thank you, there's a couple things I would change but it's definitely a solid well thought out build and your high level attention to detail is obvious.

Do tell. For me it’s mostly the lower receiver bits and bobs (and main human interfaces) that I’d change up.
 
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I regret not doing a small frame MML, I’ll say that as I look over at my matched Mega billet set with M89 rail last time I built a DMR. Maybe I’ll sell the upper and build a new one. 🤔



Do tell. For me it’s mostly the lower receiver bits and bobs (and main human interfaces) that I’d change up.

I obviously don't know the OP's circumstances, he may of had a lot of those parts laying around but if buying new I would have saved a little money with that style of two stage trigger and went with the MBT with JP springs. The SD-E just doesn't offer enough of an advantage over the MBT to justify the price.

Judging by the OP's choice of muzzle device he's not going to run a suppressor so I would have gone with a RCA or JP Low Mass BCG and a SCS.

And lastly I'm a huge fan of the APA Gen3 Adjustable Muzzle brake, the combination of the 20" medium weight barrel with rifle length gas, adjustable gas block and muzzle brake along with the low mass BCG would be just about perfect for a precision rifle.
 
Thank you, there's a couple things I would change but it's definitely a solid well thought out build and your high level attention to detail is obvious.

A lot of people on here just seem to pour their money into the wrong areas of their builds, like buying a quality matched receiver set but a shit barrel.


You started with a solid receiver set that utilizes a unique design that increases accuracy over the traditional barrel nut to handguard design.

Picked a quality single point cut barrel at the perfect length for the smoothest operation, best barrel harmonics and optimal velocity.

Proven Two Stage Match Trigger, (throw a JP Yellow trigger spring kit on it you'll like it even more)

Choosing BCM for your operating parts was very smart as well, may not be the "smoothest" option but will definitely serve you well and not affect accuracy.

All other aspects are basically user preference but all solid choices.

Let us know how you like the Muzzle Brake, I've watched a couple videos on it but have no real world experience with the Hyperfire MB.
I obviously don't know the OP's circumstances, he may of had a lot of those parts laying around but if buying new I would have saved a little money with that style of two stage trigger and went with the MBT with JP springs. The SD-E just doesn't offer enough of an advantage over the MBT to justify the price.

Judging by the OP's choice of muzzle device he's not going to run a suppressor so I would have gone with a RCA or JP Low Mass BCG and a SCS.

And lastly I'm a huge fan of the APA Gen3 Adjustable Muzzle brake, the combination of the 20" medium weight barrel with rifle length gas, adjustable gas block and muzzle brake along with the low mass BCG would be just about perfect for a precision rifle.

The barrel was probably my hardest decision on this build. I just happened to stumble onto the proof stainless and looked at specs and it fit weight and contour I was after without fluting. I’ll let you on the brake after I spend more time with it. I’m a big fan of Ultradyne brakes but I didn’t want a long brake and they are long. This one is very compact and according to their test belong to compete or beat some very good brakes so we’ll see….

I will check on the JP trigger springs too.

On triggers I actually ordered both the Larue MBT2-S flat and Geissele SD-E. I have always preferred single stage triggers and so I put Elftmann Match pro’s in both my AR308 and my wife’s AR15. I do really like that trigger, very much but you can have a bump fire on my AR308 if you don’t use correct technique with the super short reset which made me decide to try two stages (my wife actually loves a two stage now). Back to the Larue & Geissele, I ordered both because reviews were both ways taking price out of consideration but I felt like some wanted to justify the extra expense of the Geissele so figured what better way to know than order both. I installed the Larue in my wife’s since it came in first, she loved it so I left it and the Geissele in this build. Me honestly I could take things from both triggers to put into one to make the perfect trigger for me. Larue is perfect on the 1st stage, little heavy to me on the second, with the very slightest amount of creep before breaking. The G is to heavy on the front, about perfect on the second stage with zero creep and an amazing break. I hope to spend more time with both soon. I do think the Geissele is over priced at the 240 and is only worth it when on sale around the 140-150 mark compared to the Larue.

I was highly considering the JP scs and had it on my list. But a few folks swayed me to the Vltor A5 or BCM mk2 recoil mitigation system. Right now I do have sone lock back issues in the bcg and empty mag with the gas wide open so I ordered a lighter buffer which should hopefully fix it and get to run it more at the range.
 
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Clean build.

Nice choice in the coating.

I wish I had the discipline to do a monochromatic build. I always end up laying up 600 stencils and spraying six colors, even when the plan was to do what you did.

I have built on MBTs and G triggers. There is nothing wrong with the MBT and they perform as designed. I prefer the feel of the Geissele.

We all have small personal preferences that guide our choices. I'm sure I'd be happy if you handed me that rifle.
 
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Very nice build with the Mega's and Proof. That was a sad day in the MSR world when Mega closed up shop.

While they don't make billets, the Expo Arms receivers that Primary Arms sells matches my older Mega builds nicely.
 
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Very nice build with the Mega's and Proof. That was a sad day in the MSR world when Mega closed up shop.

While they don't make billets, the Expo Arms receivers that Primary Arms sells matches my older Mega builds nicely.
Thank you

Zev has started back making Mega sets
 
Thank you

Zev has started back making Mega sets
I like the Zev's as some have the correct Atom roll mark but the color and finish are off. I prefer the Expo's if trying to match an original Tumwater Mega, really hate I sold all my spares years ago.
 
I like the Zev's as some have the correct Atom roll mark but the color and finish are off. I prefer the Expo's if trying to match an original Tumwater Mega, really hate I sold all my spares years ago.
I can’t comment on the original Mega set, This is my first. From research on here I felt like I missed out with them discontinued until I discovered Zev was back making them. I got to say everything from upper/lower/ handguard locks up like a vault and the barrel was a thermal fit.
 

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I have finally had some time try tuning a load for it. I wanted the 73 gr ELD-M to shoot so bad but I just can’t consistently keep it below 1 moa, same result in my other guns. So I went to the tried and true 77 gr SMK & minimal load development.
 

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I have finally had some time try tuning a load for it. I wanted the 73 gr ELD-M to shoot so bad but I just can’t consistently keep it below 1 moa, same result in my other guns. So I went to the tried and true 77 gr SMK & minimal load development.
SMK's almost never don't work but the new world 1,000 yard shooter want higher BC................sometimes they are accurate, sometimes not.

And the old SMK plods on........................

Good shooting, great rifle.

MM
 
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I have finally had some time try tuning a load for it. I wanted the 73 gr ELD-M to shoot so bad but I just can’t consistently keep it below 1 moa, same result in my other guns. So I went to the tried and true 77 gr SMK & minimal load development.
I had the same problem with Hornady's factory loaded 73 ELD-M ammo, just piss poor accuracy out of two of my guns so I gave up. I heard the same thing from other people too.
 
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I had the same problem with Hornady's factory loaded 73 ELD-M ammo, just piss poor accuracy out of two of my guns so I gave up. I heard the same thing from other people too.
There’s a thread in reloading subforum loaded (heh) with complaints about them I’m pretty sure.
 
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I had the same problem with Hornady's factory loaded 73 ELD-M ammo, just piss poor accuracy out of two of my guns so I gave up. I heard the same thing from other people too.

The bullet itself is capable of acceptable precision. The 10-shot group pictured below was fired from a semi-automatic AR-15 with a hand-load of the Hornady 73 grain A-MAX/ELD and has an extreme spread of 0.82". Unfortunately, as you stated the factory load falls short of expectations for a lot of people. And as others have stated, the standard 77 grain SMK is a safe bet in most any decent barrel. A 10-shot group of the 77 grain SMK fired from the same AR-15 had an extreme spread of 0.56".



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......
 
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What was wild was that the velocity ES and SD numbers from the 73 ELD-M's were great for factory match ammo, didn't match at all what I was seeing downrange but the bullet tells the tale.
 
Clean build.

Nice choice in the coating.

I wish I had the discipline to do a monochromatic build. I always end up laying up 600 stencils and spraying six colors, even when the plan was to do what you did.

I have built on MBTs and G triggers. There is nothing wrong with the MBT and they perform as designed. I prefer the feel of the Geissele.

We all have small personal preferences that guide our choices. I'm sure I'd be happy if you handed me that rifle.
To be honest I almost decided to camo this rifle last minute before sending to cerakote. Of all people my wife talked me down and to stick with what I planned. She can be great at times 😁 and thank you.
Yes, he did....................outstanding rig !!

Congrats.

MM
Thank you!
SMK's almost never don't work but the new world 1,000 yard shooter want higher BC................sometimes they are accurate, sometimes not.

And the old SMK plods on........................

Good shooting, great rifle.

MM

The extra BC is nice if it worked but I honestly wanted it to work badly as a do all bullet with the plastic tip (better expansion) for predators, deer/hog, and the range. I guess when supplies catch up some more and hopefully cost comes down sone I’ll try some TMK’s.
 
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She's looking good brother, That's one of those builds you'll never want to get rid of, just swap out the Barrels and keep on shootin.

I'll be starting a 6 ARC build here soon.
 
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She's looking good brother, That's one of those builds you'll never want to get rid of, just swap out the Barrels and keep on shootin.

I'll be starting a 6 ARC build here soon.

Thank you Jake. The more I shoot it the more I really like the gun and don’t regret the time and expense I put into it.

I look forward to your 6 ARC build. That caliber really interest me but I couldn’t do it, waiting on it to catch on more and components to catch up.
 
I had the same problem with Hornady's factory loaded 73 ELD-M ammo, just piss poor accuracy out of two of my guns so I gave up. I heard the same thing from other people too.

My rifle hates every Hornady I tried...68gr, 73gr, 75gr...not a single one could hold under 1.5" @ 100m. Good ol' 77gr SMK comes along, and now the rifle wont shoot over .75" @ 100m. Best part is, the rifle is a very inexpensive Ruger American Ranch 5.56.
 
SMK's almost never don't work but the new world 1,000 yard shooter want higher BC................sometimes they are accurate, sometimes not.

And the old SMK plods on........................

Good shooting, great rifle.

MM
Meh I want a heavy polymer tip for terminal affect. Not many out there besides the TMK. Is. Sucks the eld doesnt shooot. Was about to buy some
 
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