Which Upper?

[iMagUdspEllr]

My custom upper that I assembled did not make me happy. I discovered that you pretty much have to "eyeball" the flash suppressor, gas block, gas tube, and barrel nut (not to mention have the flash suppressor and barrel nut torqued properly) in order to assemble the upper receiver.

I was fine with it for a while. But, when I discovered that my barrel's feed ramps were cutting the bullets as it chambered them, I had enough. It looks like three cuts on the bullet (as if it is skipping into the chamber). It isn't the normal lines you get when the bullet is dragged across the locking lugs (when you extract an unfired round). I was told that you can easily smooth the feed ramps out with a dremel. This might be just me... but I like things made correctly... and I'm not happy that I have to take a dremel to a brand new barrel.

So, since I want it to be put together correctly and I'm not happy that I have to eye-ball five things that need proper alignment... I caved and decided to just buy a pre-built upper. I figure it is better to let machines or experts align these items than me.

I am looking at either of these upper receivers:

Daniel Defense M4 URG, v5-300 AAC Blackout
https://danieldefense.com/upper-rec...aniel-defense-m4-urg-v5-300-aac-blackout.html

or

LaRue Tactical 5.56 Stealth Sniper System LT011
http://www.laruetactical.com/larue-tactical-stealth-sniper-system-lt011

Yeah I know *gasp* .300 BLK. Pretend it is the DDM4 v5 5.56 if the .300 blk gives you heart burn.

 

[DasGuy]

I'd go the the DD because they have chrome lined barrels, LaRue doesn't. The LaRue will be a little more accurate due to that, but you'll have to replace the barrel on it a lot sooner than the DD.

 

[Mobuck]

So much for the simplicity of "building an upper".

 

[iMagUdspEllr]

@DasGuy: Thanks. I thought they were lined with something due to the black appearance, but apparently not.

@Mobuck: Yeah lol. No kidding. Its simple... just not simple to line everything up perfectly.

 

[Crow Hunter]

What do you want it to do?

I would decide that 1st.

It can really change which upper is most suitable. (Super accurate lower durability vs combat accurate higher durability or mix and just plain higher cost)

Another idea:

You already have a very good 5.56 defensive rifle. Have you thought about going with the SCAR 17 and really opening up your performance envelope (effective range and penetration) but still keeping the same manual of arms and spare parts commonality?

I am babysitting one now, along with a Larue PredatAR in .308 and a SCAR 16 and that SCAR 17 really amazing.

Just picking one up with your eyes closed makes you wonder which one you have picked up. It is that light.

Especially when you compare it to a Colt 6920 vs the Larue.

 

[iMagUdspEllr]

@Crow Hunter: Combat accuracy is what I'm leaning towards. Trajectory of 3" above/below the front sight from 0 to 200 yards (it looks like .300 blk can do that out to about 240 ish depending on barrel length/load.)

I like my SCAR. However, I don't like how "tall" it is (in the hand guard area due to much of the bolt carrier being located there). I prefer the ergonomics of an AR to the SCAR (at least right now... today).

Have you thought about going with the SCAR 17 and really opening up your performance envelope (effective range and penetration) but still keeping the same manual of arms and spare parts commonality?

SCAR 17 is on my list assuming I fall out of love with AR ergonomics. But I'm still trying to get an intermediate rifle that is right for me.

There aren't many spare parts readily available for SCAR's, in general. So that is another reason why I want to get an AR that I'm happy with.

 

[Crow Hunter]

I like my SCAR. However, I don't like how "tall" it is (in the hand guard area due to much of the bolt carrier being located there). I prefer the ergonomics of an AR to the SCAR (at least right now... today).

I am in the same boat as you there. I have thought long and hard about "upgrading" my guns from AR centric to SCAR centric, just because of how much I like the SCAR 17 weight/balance/performance versus the "AR-10" type rifles that I have tried (and others).

It is quite a bit taller, which also affects hold over at close range. Even worse than the AR, and I also like the charging handle position for the AR over the SCAR. I skin my knuckles on the optic mounts on SCARs and I have interfered with functioning with it mounted on the left side on a SCAR.

While there are a couple of places now that you can get spare parts for the SCAR, but they aren't as available as the AR and they are quite a bit more expensive.

Plus, with the AR, the lower has the serial number, so you can just switch to a new caliber with 2 pins and still keep your optic sighted in. The SCAR (if they ever release them, which I don't think the factory ever will) requires more work to change and you have to sight your optic back in.

Plus, the AR is much more common, so if you ever had pick up a fallen weapon and use it in an emergency, the AR would be much more likely to be the weapon you will find.

There also aren't any magazine restrictions with the AR like there are with the SCAR. (Don't use certain magazines without modifications or you risk damaging the rifle)

But, man that SCAR 17 sure is light and handy.

Especially compared to the AR-10, M1A or FAL that I have shot and the HK 91 that I have handled.

But honestly, I don't need the .308 power envelope for my uses in anything other than a hunting rifle, and the AR-10 type is fine for that.