Hey guys can somebody give me some advice on which way to go with building a upper...I'm going with a 16" so I can use this for hunting, will also be suppressed soon and will be the "general purpose" rifle.
    Should I go pistol gas system or mid length? 1-7 twist or 1-8 twist

Pistol length gas system seems to be the most versatile, and 1-8 is a good barrel twist for the range of bullets you'll likely be shooting.

Thanks for the info  

I have found a complete upper from Novenske has everything I want except the twist is 1-7" .....any suggestions who builds a better suited "general purpose" upper than Novenske?

My 16" .300blk, I went with ballistic advantages 16" pistol length barrel. It runs great. I have yet to try it supressor though.

Would only run pistol gas if you ever want to run subs through it. Carbine if it is to be dedicated super gun.
Pistol gas is pretty easy to overgas especially supressed.

I wouldn't sweat the 1:7 and just enjoy the Noveske. It'll do what you want.

ordered the Novenske upper this morning, went with the rouge hunter....looking forward to getting it.

Now to consider a optic, I have started the search but oh my there is a ton of info to process

Food for thought...

My .300blk is a 16" carbine 1:8.  I run both supers and suppressed subsonic (208 grain Amax, mostly Freedom munitions) through it well...

To me the pistol gas systems over gas...

YMMV

Wilson Combat pistol gas lightweight

or

Wilson Combat carbine gas recon


I run the Wilson Combat carbine gas lightweight (which he seem to have dropped)...

I have the Burris Fullfield TAC 30 on my 300 Blk.  Seems to cover most eventualities.

Realistically the practical range of a 16" 300BLK, even with supers is about 300M (yes the bullets fly farther, and yes there are good demonstrations of it making hits at much further ranges).   My definition of practical is where the bullet still has a useful trajectory and energy to do what I need it to do, such as taking medium game.   Even at that, I personally limit it to 200yds for reliable shot placement and bullet expansion, but that is my own rule.   You can certainly go with a lot of magnification, but the big draw of the 300BLk is certainly for shorter range work.  A good 1-4 optic, perhaps with some level of BDC would be a good do it all optic.

I installed the Nikon P-300BDC on my 16" pistol length upper. I'm still waiting for the phone call from my dealer that my lower is ready for pick up.
Fuckers have had it in the back room since Wednesday dragging their ass on checking in the UPS shipment I guess.

ETA potato-pic of completed rifle. PSA 16" Pistol Length 300 AAC Blackout 1:8 twist. 13.5" M-lok Upper, Blem PSA AR-15 Complete Lower Magpul ACS-L, Nikon P300-BDC on a Burris PEPR mount.

Nice rifle man   I will try to update post with pics in the next 24 hours.

The build is nearing completion..... I ordered the Sig sauer tango 4, 1-4x24 scope with the 300blk out reticle from optics planet with the sale and coupons it was a reasonable solution and has everything I wanted in a scope, if it works as advertised then it will be well worth the scratch.
     My next issue is the optic mount I called larue and the mount I want is back ordered with no eta at this time and I'm not sure it would work with the scope anyway so I'm searching for a reasonable facsimile

Here is the build specs so far:
16" Novenske rouge hunter upper with kmr and pistol length gas system
Is on the spikes hog billet lower
Pof drop in trigger
Seeking precision mag release and safety selector
I put the minimalist stock on the build

Think that is it so far??   I will post a pic of the build this weekend.....

Only thing I do not like so far is the lower is billet and the upper is the novenske standard a3 upper so I have some slight wobble that will drive me crazy!!!  Otherwise I'm in love with this setup already and I haven't even shot it yet lol

Concern: I have the regular 556 buffer and spring in it right now, should I go ahead and replace now or wait until test firing to see how it functions?

I got a Seekins barrel that is 1/7 in carbine gas system. Works great with subs and supersonic loads. I'm? currently using a carbine weight buffer.

Sounds like a great build!   I'd start with the carbine buffer and take a look at function and ejection pattern, and then see if you want to go heavier.  I personally like the H2 buffer.

Built a pistol in 300blk out as well went out yesterday to shoot it with the green and white box Remington in 120grain and the 220 grain.
  Everything seemed to run ok for all 80 rounds with the exception that on the last round with subsonic ammo the bolt would not lock open, I also noticed quite a bit of brass residue on uppers brass deflector......I was using the standard weight carbine buffer with pistol buffer and spring from phase 5, barrel is 8" and I'm using the lantac bolt, do I need to go with a heavier buffer?

There are several ways to go in barrel and ammo options in suppressed and non-suppressed applications.  Personally I'd go with two uppers.  I like keeping one application strictly for suppressed and one for supers.  A 9" or so...I use a 9.5" BA barrel...300BO in suppressed mode is about the ideal spot when using a suppressor.  A 16" barrel is one of the best compromises for using supers...plenty of ballistic performance in a handy size for hunting and such.

Prices for complete uppers and/or upper components are at an almost ridiculously low level right now.  Build two uppers for suppressed and unsuppressed use, and you can ideally have them dialed in for each separate use without any fiddling and headaches.  This is just a suggestion, and of course it's not the only avenue to achieve what you want.

Are you using a suppressor? If not keep it exactly as it is. It sounds like you have the perfect size gas port. You are not too over gassed when shooting supers and just barely gassed enough when shooting subs.

It seems to be feeding fine and if you add a suppressor to it then the subs will cycle even better and hold the bolt back with no problem.

The brass on the deflector is common as the case mouth on the brass hits the defector leaving an imprint and some brass shavings and is completely normal.

Not using a suppressor yet but plan to begin the process soon. The rifle performed flawlessly with the exception of the bolt locking back on only the 220 grain bullets.....this combined with the overall shortness of the rig has me leaning twords setting this up as my go to home defense rifle. If this is to become the home defense weapon I would want to use between 150 grain and 220 grain as my main round?
   I didn't think the brass tracks on the shell deflector was a big deal but it was more than I was used to with my other caliber ars' so I wasn't sure if this was a symptom of another issue

Attached File




Here is both builds so far

Ok sounds like your rifle is good to go exactly as it is. Shooting subs without a suppressor isn't encouraged as it is only slightly quieter than supers and lack the power that supers have.

As for home defense ammo goes typically the lighter grains for supersonic work better as they don't penetrate as far as the heavier ones. A lot of people like the 110gr barnes black tips but if you don't want that much penetration there are the 110gr Vmax bullets and you could also use Lehigh's defense 115gr or 110gr controlled chaos rounds.

If you want to shoot subs as your home defense like I do make sure you have your suppressor first as I would not consider the backpressure on your rifle without a suppressor reliable enough to guarantee extraction of all rounds. I would also use an expanding subsonic as a 220gr non expanding bullet will penetrate just about every wall in you and your neighbors house.

Subsonic expanding bullets are a little pricey but for home defense it is well worth the price. By having the ability to not blow out your eardrums and keep the flash to a minimum inside the house. My favorite is the Lehigh defense 194gr but there are a couple other manufactures out there that will expand at subsonic velocities.

BTW nice looking rifles

Thanks for the info, that is exactly what I was looking for. I have very little experience with 300 black out except YouTube video and what I have read here lately as I have tried to research.
You may have inadvertently helped me make a decision on a optic for the pistol as well, I had it narrowed down between the eotech 300BO sight and the trijicon MRO. With what you are advising me the function of two dots for SS and subs would be kinda useless making the MRO the first choice for optic I think.......arrrrguh!

I had exactly the same issue.  Bolt wouldn't lock back on an empty mag on the Remington supers or subs.  In fact, I tried about a half dozen big name factory loads and it had the same issue with basically everything.  Jim Bob's Ammo 120gr supers must be a little hot, they worked perfectly.  Perfect function otherwise.  Haven't tried suppressed yet, no $ in hand for the stamp right now.

For a given amount of kinetic energy imparted to the bcg, you need it to move farther rearward.  Nowhere in PEs=1/2kx^2 is mass of the buffer.  Increase the mass, it moves the same distance, just slower.  Change the spring rate of the buffer spring, though, and that changes distance traveled.  Remember, unless you decide to open up the gas port or change ammo, the energy coming through the gas system is the same.  

So my $35 solution was a Springco reduced rate buffer spring.  Works great now with all ammo.  Carbine gas Anderson 16" barrel.  I've only got about 400 rounds through it, if it loosens up a bit as I use it I might try putting the standard rate spring back in.  No opening gas port, no changing barrel or gas block.  Just pop the buffer and spring out and put the different spring and the same buffer back in.  30 second fix with just hinging it open.

YMMV, I may be full of shit, and this is only my second AR assembled.  But I did spend a few years studying Physics and it worked like a charm.  Worst case you're out $35.

Slight difference in your problem and it is a problem.

The OP has his gas system, spring and bolt set up perfectly. As the only time it isn't locking back is on the subs because there isn't enough backpressure without a can. This is a near ideal gas situation where it isn't over gassed on the supers and it is perfectly gassed on the subs.

Yours is another problem with the rifle when you can't even get the supers to lock the bolt back. Sounds like the gas port is too small, the gas block is misaligned or there is a leak somewhere in your gas system.

What barrel are you using? I'm sorry if I missed this somehow.

I used the 8" CMMG barrel, has a lantac gas system and lantac bolt.....bolt is super nice, and the gas ports vent twords the front of the rifle instead of my left handed face lol .. Also equipped with a spikes tactical barking spider muzzle device that I think is giving me a little back pressure perhaps