Need advice on 2nd 300BLK SBR Build

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voip-1
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Need advice on 2nd 300BLK SBR Build

Post by voip-1 » Sun Nov 15, 2015 12:10 pm

Hey guys,

I've gotten the bug to build a 2nd 300 BLK SBR. This SBR will become my primary SBR and my original build based on an AAC 9" upper will become my secondary gun (primarily because I kind of hate the billet lower I used in that build).

One impetus for this is that I think that we will see changes to rules around NFA Trust before the end of Obummers 2nd term and I'd like to have at least one more SBR before that happens.

So here's what I'm thinking I'm going to do as this will be the first time I try to build an upper myself.

1. Aero Precision M4E Enhanced Upper. This upper is specifically designed to ease barrel and hand guard installation. The only drawback is it can be a little trickier to get the gas tube lined up due to the thicker interface at the barrel nut. Well, there is one other very small drawback which is that this upper has slightly different surfaces than "standard" uppers and might not fit tools needed if I ever wanted to fit a 6.8 barrel or do certain other things with the setup that I am not likely to ever do.

2. Aero Precision lower.

3. Aero Precision 7" M-Lok or Keymod hand guard... all of my other stuff is Keymod but it might be kind of nice to check out the competition for this build and since swapping the hand guard with the M4E upper is super easy I can change it out later if I like for about $130.

4. Noveske 8" 300 BLK barrel. My LBS will sell me this barrel (which includes gas block and gas tube) for $275. I don't want to cut corners on the barrel but if anyone has what they feel is a better choice I'd love to hear it. I've contemplated between the 8" barrel or going to a 10.5" since I normally prefer a slightly longer hand guard so any input here is welcome.

5. Regular stuff for lower parts kit, buffer tube, etc. I will actually re-use a spring/buffer setup from my 1st build as I ultimately replaced it with a captured buffer.

6. For furniture my current go-to setup on my other carbines is the BCM grip and the Magpul MOE SL stock. I love that stock and have it on three of my rifles now.

7. To make things "fun" this time around I think I might do the upper/lower in black and then do the grip, hand guard and stock in FDE.

Interested in any input anyone can provide.

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rpk47
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Re: Need advice on 2nd 300BLK SBR Build

Post by rpk47 » Sun Nov 15, 2015 1:45 pm

The only thing I would change is the upper. To me that seems like a solution looking for a problem. Plenty of free float hand guards that are very good and don't require a different upper to work. On the other hand it seems totally functional and it is different so, if it's what you want I say go for it.

Second point is Noveske barrel, mine is great I have no issue with gas using the supplied gas block under any configuration of ammo/suppressor. My chamber is a bit tight however, this doesn't cause any issues. You only need to be aware of this if you reload your own ammo due to pressures being slightly elevated compared to a non match barrel. I think they have since changed to not be match barrels and don't have as tight of a chamber, tho I could be wrong on this.

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Overton-AR
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Re: Need advice on 2nd 300BLK SBR Build

Post by Overton-AR » Sun Nov 15, 2015 2:00 pm

1 - Aero Precision is awesome, don't get me wrong. However their enhanced series will cement you into a place that you may not want to be in the future. Go with their standard upper receiver and then you aren't locked into "their" rails. Their are much better choices for rails that all use standard mil-spec upper receivers.

2 - Excellent choice. Aero makes great lowers.

3 - Lots more choices for rails when you get away from the "enhanced" upper. My current favorite is the Bravo Co KMR. I am a huge fan of key mod.

4 - Noveske makes great barrels. I have 3 of them with no complaints.

5 - The silent spring is worth the investment. :mrgreen:

6 - Furniture is personal. Get what you like.

7 - Again.....color is a personal choice. I did the black/FDE 2-tone look.

BlogSarge
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Re: Need advice on 2nd 300BLK SBR Build

Post by BlogSarge » Sun Nov 15, 2015 3:16 pm

Since you like a longer handguard, get the 8" barrel and screw a suppressor onto it which will give you a 14 to 16 inch barrel+supp length. Be sure to get a handguard that fits over the suppressor.

TMD
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Re: Need advice on 2nd 300BLK SBR Build

Post by TMD » Sun Nov 15, 2015 3:38 pm

1. Aero Precision M4E Enhanced Upper. This upper is specifically designed to ease barrel and hand guard installation. The only drawback is it can be a little trickier to get the gas tube lined up due to the thicker interface at the barrel nut. Well, there is one other very small drawback which is that this upper has slightly different surfaces than "standard" uppers and might not fit tools needed if I ever wanted to fit a 6.8 barrel or do certain other things with the setup that I am not likely to ever do.
I have two M4E uppers for my SBR's and am totally impressed with them. The gas tube being outside the barrel nut is probably one of the best features. No need to use shims on the barrel nut when torqueing it down so aligning the gas tube hole is never an issue. I will say though that the barrel nut wrench they provide is a piece of crap. Its cast and the slightest little slip will brake off one of the teeth. Only other disadvantage is that you are limited to their hand guards. Thankfully they offer three different types in several different lengths.

voip-1
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Re: Need advice on 2nd 300BLK SBR Build

Post by voip-1 » Sun Nov 15, 2015 4:10 pm

Hey guys thanks for all of the input so far.

My main reason for leaning towards M4E is that even though I've assembled a bunch of stripped lowers before this will be my first upper assembly and I'm nervous about messing something up using shims, lining up gas tube, getting proper torque on barrel, etc.

My understanding was that the M4E is also compatible with B.A.R. profile hand guards so you are not completely limited to Aero for hand guards but then again I haven't looked into what is available on the market.

Another plus for me was that I could choose an Aero pre-FDE dipped hand guard vs. having to spend $100-$200 having a hand guard cerokoated for the look I am after.

Definitely as secondary choices both Bravo Company and Midwest industries are putting some really nice hand guards out on the market. Geissele also has some nice looking stuff.

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rebel
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Re: Need advice on 2nd 300BLK SBR Build

Post by rebel » Sun Nov 15, 2015 6:25 pm

Put a good trigger in the build.
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voip-1
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Re: Need advice on 2nd 300BLK SBR Build

Post by voip-1 » Sun Nov 15, 2015 6:47 pm

rebel wrote:Put a good trigger in the build.
Yes, my plan is for a 3 or 4 lb velocity trigger. I just got one of their triggers this week and it is pretty incredible for $120.

voip-1
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Re: Need advice on 2nd 300BLK SBR Build

Post by voip-1 » Tue Nov 17, 2015 11:14 am

BlogSarge wrote:Since you like a longer handguard, get the 8" barrel and screw a suppressor onto it which will give you a 14 to 16 inch barrel+supp length. Be sure to get a handguard that fits over the suppressor.
That's not a bad idea but I still might be better off going with a 9" hand guard and a 10" barrel. It's what the military is currently issuing to the "cool guys" and they use suppressors plenty of times with that carbine length and don't seem to run into any trouble mounting all their gadgets either.

voip-1
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Re: Need advice on 2nd 300BLK SBR Build

Post by voip-1 » Tue Nov 17, 2015 11:21 am

So my second choice at this point would be this;

1. Aero 2nd gen lower + complete upper. ($199)
2. BCM KSM 9" rail ($250)
3. Noveske 10.2" barrel + gas block + gas tube. ($275)
4. BCM BCG ($175)
5. CMMG LPK ($40)
6. Furniture ($80)
7. BCM buffer tube ($60)
8. AAC muzzle brake ($60)
9. Velocity 4 lb trigger ($135)

== $1274.

plus of course $200 for the tax stamp (ouch)

The way I look at it, going this route is going to cost me only about an extra $150 over going the M4E route and assuming I can complete the install without too much trouble I would have a much more standard rifle setup. I could also swap the 300BLK barrel down the road if needed for 5.56 and just notify the ATF of the caliber change. I think I would have better results swapping 10" barrel than 8" if I ever decided to go that route.

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