BUILDING A 300 BLACKOUT UPPER: STEP BY STEP

Could I use an 8 1/2" barrel for my build? Thanks, Jay

Will geissele's super gas block work under that mk2 rail?

Very well made and helpful. Great build, I'm very jealous. Thank you sir, you earned a sub!

Hurry up and finish that upper! Someone is screaming for "HELP"!

What vice block did you use for this build?

Love all the detailed info especially deezzz nutz forsure! Lol. Great info for anyone wanting to build a 300 blk upper. Keep up the awesome videos! Thanks

tank's mate!!! very educational

How has the Hand guard worked out?

2017 and this gun has blown up in popularity dude was dead on

what ist the distance for the gas port location…4 inches ? its a pistol gas system right ?! and what diameter isf the gas port hole in the barrel ? works it with subsonic and supersonic ammo ?

BBQ Pit Boys intro??

would you upper shoot subs and super ammo?

Magtech/Sellier and Bellot have fjm in 300blk for about half the price of a hollow point.

from my experience u need to grind down the inside of the metal mags if u don't it won't feed reliable

very informative video! do i have o worry about head spacing when attaching a barrel to an ar15?

Love 94% of this very helpful and well produced video. Missing how to install tiny C clamp doohickey on to rod that holds dust cover. Missing the intricacies of mounting the strange spring that flips open the dust cover. Missing how to install gas tube on to gas block. Need to show how gas tube mounts directionally relative to barrel nut. Would have been nice to se the shim selection process. Beautiful build.

Great video, just one question. Do you need to get any dedicated 300 blackout gas blocks/tubes, or do you just use standard .223/5.56 parts?

I'm pretty sure when torquing the barrel but, you need to season the threads by incremental torquing and removal.

Im sorry great Vid but im lmao at 11:48. Lock tight the bottom of THESE NUTZ

so do I just quote the serial on my preexisting lower to the atf when I build an SBR?

How's the Rainier Arms barrel been doing? I'm debating on a BCM 300 9" and the RA barrel which is a lot cheaper than BCM too. please let me know what your thoughts are so far with this one. thank you

Step 1: Purchase a Ruger Mini 14 300 Blackout

The end

I think the 300 is the new 15

What did you put into the upper receiver block right at the beginning pls?

did anyone hear a scream help at 12:07

the gas block suppose to go all the way forward on the barrel

Very informative, thanks for taking the time to put this on here, you have inspired me to build one.

OK build. I would have gone with an adjustable light weight piston gas block like the 18 way adjustment Syrac. The entire kit only adds up to maybe 2 more ounces than a DI. Less when Syrac comes out with a Low Mass carrier.

The Geiselle rail is quality, but I would have avoided it no matter how good a deal I got. LOUSY ergos. The Geiselle rail is horrible to hold. The market is FULL of low cost, light rails that are waayy more comfortable than the Geissele.

Go for the Omega. It may not be as quiet as the SDN but it is so much lighter. I like that Omega has Stellite baffles. Stellite is tough and light. The Omega seems to be one of 2015's most popular cans.

The Syrac with 18 adjustments is almost mandatory for tuning with a suppressor and different loads of 300 BLK.

ANY kind of adjustable gas block for a build like this is mandatory for best results.

The muzzle device installation part…. That was intense!

11:47 "deez nuts" hahhaha

@11:49 deeeeez nuts lawwwwwl

Shocked you didn't you AAC's or another thread lock for you muzzle brake…its required and needed….

Why are you beating on your upper with a regular hammer, why not tape? Other than that good video though.

I started omitting the dust cover and forward assist on ALL my upper builds. I have not really missed them in many thousands of rounds in all kinds of conditions. I would include them if I were going to war in desert conditions. Otherwise, I have quite liked those two items to simply be of zero importance…since they dont exist on my uppers.

 I dont suggest using a gas block with set screws…ever. Clamp on versions are 1000% times better/more reliable. A single dimple is of little advantage. I have actually had dimples NOT match up with the optimal gas block alignment. Go CLAMP ON…always. I use RED loctite always on gas blocks. Never use blue! I speak from many, many builds and rounds down range. Set screws on a gun is just a bad idea all around when there are other FAR better options.
Actually, I do want to need a torch to remove my gas block. So far, I have never had the need to remove any of my adjustable gas blocks anyways. I bed them as well with a special 600 series green loctite. I bed my gas tubes as well for zero gas blow by and zero carbon build up where carbon should not be seeping in to.

Sweet vid.   Best camera work/angles I've ever seen.   A question if I may.  I wound up selecting a 16" rifle barrel with a pistol length gas port.   I plan on running subsonic loads in it.   I plan on using ungas-checked cast lead rounds with some sort of suppressor (I haven't made up my mind).    My question is:   Are there any issues with my 16" barrel but only having a pistol length gas port/tube?   I've read that they can have cycling issues but it seems to me that if anything – the bolt will have more than enough energy to cycle.    Do I have to select a softer spring or select a different buffer?    I own most all of the weights of the various buffers so I can easily experiment.    Your thoughts please.

I'd like to share the following note from a friend of mine (not my comments).   He's probably forgotten more about things than you and I will ever know.   He said:
Subsonic loads require heavy bullets (~190-220 gr) to have decent energy. The velocity needs to be <1140 fps to avoid the sonic crack. This gives ~635 ft-lb of muzzle energy (similar to 357 Mag, so its no slouch). Non gas checked cast bullets would probably work great at this velocity. Plus, these loads would be easy on powder and the pocketbook (I estimate 7.7 gr Alliant 2400 would give 1143 fps with a 220 gr cast bullet and cost ~$0.06/round).

That barrel looked like it was more difficult then normal to put in.

It  looks like the angle of the gas tube was hitting the barrel nut and wasn't allowing the block to move all the way back to seat properly. Did you have any cycling issues?

thanks for the excellent video.  i'll be using your guide when all my parts arrive.  I've a question regarding the vise size.  I see you are using a 4" vise.  I currently have just a 3" vise and was wondering if I need to get a bigger one or will my 3" work?  I will be buying the wheeler delta series upper vise for my assembly, i think you use the same?

great video, needed a Nemo arms300 blackout  buffer spring on mine to run though. PNW blackout ammo didnt cycle with a normal spring.

Another great video, only thing I would recommend is lube.  Most parts would do better with a little bit of oil.  It helps make things go in easier and protect the inevitable scratched finish which could cause binding if you ever decide to remove anything.  I'm talking about things like roll pins and even the dust cover pin.

Great video. Would applying heat help put the rail on? Also add a piece of electrical tape around the muzzle device when using a crescent wrench helps keep the finish nice. Thank you

Great video, in the process of building my 300blk upper. Only stuck on the gas block. Trying to determine between adjustable or standard…would like to do standard Lo-profile to save the money but am going to be running 8" barrel mostly suppressed. Any issues with yours being over-gassed or do you recommend an adjustable anyway? Thanks!!