300 BLK Upper build.

[P-12 Norm]

Got as decent deal on (2) Bravo Company stripped uppers, and am putting together the first build as a .300 BLK. Got an ARD barrel off Gun Broker, pistol length gas, 16" heavy barrel .750 dia. Toyed with the idea of a piston action, but have decided on an adjustable gas block impingement system. Trying to figure out the hand-guard size to get, and what height gas block. I like a longer guard, but I also want ease of adjustability, as I might/probably will get a can for it later.
And while I have assembled some AR lowers, this is a first as far as an upper goes. Youtube only helps so much...

 

[Bountied]

Not trying to be rude but is there a question in there? If you have a 16" barrel you'll want a 15" handguard. The can has nothing to do with it unless you are trying to do a 10.5" barrel with a 15" handguard and want the can inside the handguard, then the ID will matter. If you haven't done an upper you may need some new tools. Torque wrench, vice, clamping tool, etc. It's not hard you just need the right tools.

 

[P-12 Norm]

Yeah, sorry. My head is swimming with Google Goo.
If the gas hole & adjustable gas block are pistol length, what length hand-guard is best, seeing as the barrel is 16" and I want ease of adjust-ability? And would what is a good brand of gas block and height for adjust-ability and a longer hand guard (if that is even possible with pistol length gas port).?
Like I implied...I am all confused.

 

[BurkeM]

15 inch, for max use for future add-ons (light, grip, optics, etc)

Gas block? a very personal choice. Pistol length = pistol, etc.

 

[Bountied]

Yeah, sorry. My head is swimming with Google Goo.
If the gas hole & adjustable gas block are pistol length, what length hand-guard is best, seeing as the barrel is 16" and I want ease of adjust-ability? And would what is a good brand of gas block and height for adjust-ability and a longer hand guard (if that is even possible with pistol length gas port).?
Like I implied...I am all confused.

You can usually get to the adjustment screw on the gas block through the handguard so it shouldn't be an issue. I don't run adjustable gas blocks so I don't know much about them. I run my 300blk with a 10.5" barrel, pistol gas tube, 9" handguard, and fixed block suppressed. Haven't had any gas issues, a 16" barrel with pistol gas tube is a different story. Sorry not much help there.

 

[alucard0822]

A couple things. A pistol length gas system is about 4" long, basically any handguard over 4" will have to clear the gas block, so a low-pro gas block. If you want adjustable, most have a screw to adjust, a ball end allen wrench through a hole/slot in the side of the handguard might give enough room, or you might need a handguard that can be easily removed to make gas adjustments. Thing is 300 doesn't have anywhere near the excess gas of 5.56 ARs, and the vast majority including suppressed are just fine with a standard non-adjustable gas block. I usually run a standard 3oz to 3.8oz H1 buffer and standard gas block, and most 300 uppers run great with or without a can.

For a 16" barrel IMO 15" handguard and be done with it. Even a small cramped carbine handguard is 7" and will take a long allen key to access a gas screw about 3" from the front of the handguard. Riflespeed blocks and sleeves are about the only way to adjust a block under the guard without tools, and from ahead of it. Their longest $200+ block would allow access on a pistol gas system with a 9.5" handguard.

 

[Magnumite]

^^^ I love reading your posts. Clear, concise, and full of useful info. You should author a book.

 

[atblis]

I’d be tempted to go with a gas block that adjusts from the side. Drill a hole in the hand guard to access the adjustment screw.

 

[Rondeezy]

I’m about to start doing my build soon. Got my aero m4e1 lowers and an aero upper. Only thing I need to figure is if I wanna do a 10.5 Rosco build like my 5.56 or get a 10.5 Faxon gunner and a different bcg.. gonna do an adjustable gas block.


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[Rondeezy]

Got as decent deal on (2) Bravo Company stripped uppers, and am putting together the first build as a .300 BLK. Got an ARD barrel off Gun Broker, pistol length gas, 16" heavy barrel .750 dia. Toyed with the idea of a piston action, but have decided on an adjustable gas block impingement system. Trying to figure out the hand-guard size to get, and what height gas block. I like a longer guard, but I also want ease of adjustability, as I might/probably will get a can for it later.
And while I have assembled some AR lowers, this is a first as far as an upper goes. Youtube only helps so much...

Sent from my iPhone using Tapatalk

 

[Bafflingbs]

I went with an Aero Precision adjustable gas block, for most of my uppers. It has a 3/32” adjustment valve. I found this on Amazon, to really get some reach. It easily reaches carbine length gas blocks, with a 15” handrail. It has plenty leftover, to probably make it to a pistol length gas-block. The shaft, itself, is 11” so it should reach. I run suppressors on all of my uppers:
Bondhus 3/32' Ball End... https://www.amazon.com/dp/B000MBI9FU?ref=ppx_pop_mob_ap_share

 

[Bafflingbs]

This will work too, if you can’t find the above listed. I believe that it’s 15” OAL:

https://a.co/d/hGA3qiK

 

[P-12 Norm]

I went with an Aero Precision adjustable gas block, for most of my uppers. It has a 3/32” adjustment valve. I found this on Amazon, to really get some reach. It easily reaches carbine length gas blocks, with a 15” handrail. It has plenty leftover, to probably make it to a pistol length gas-block. The shaft, itself, is 11” so it should reach. I run suppressors on all of my uppers:
Bondhus 3/32' Ball End... https://www.amazon.com/dp/B000MBI9FU?ref=ppx_pop_mob_ap_share

Well, the Midwest hand-guard worked. And the adjustment tool you suggested I found on Amazon for $16 for 2. Plenty long, fer sure.
I would like to find out what the second contour behind the threaded portion of the barrel is for (smaller than the .750 of the rest of the heavy barrel):

(ps- any one need a long shaft 3/32" SAE ball end adjustment tool, lemme know; free to good home).

 

[P-12 Norm]

Well, got an Anderson BCG and a Strike Industries charging handle. Now all I need is the "muzzle device", and I can slap one of my lowers, put some temporary sights on it, and head to the range to test it out! (Muzzle device to arrive tomorrow, according to the USPS.)

 

[alucard0822]

^^^ I love reading your posts. Clear, concise, and full of useful info. You should author a book.

Thank you, I have contributed to automotive tech guides and industry articles, have been told they may help cure insomnia after only a couple pages LOL.

 

[Magnumite]

LOL!

 

[Tracker12]

Each barrel has a gas block size based on circumference. I like a shorter rail.

 

[Rondeezy]

Just finished my 300Blackout build. Waiting on my folding adapter to be shipped but and then to hit the range to make sure it works lol.


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[outrider58]

Well, the Midwest hand-guard worked. And the adjustment tool you suggested I found on Amazon for $16 for 2. Plenty long, fer sure.
I would like to find out what the second contour behind the threaded portion of the barrel is for (smaller than the .750 of the rest of the heavy barrel):

(ps- any one need a long shaft 3/32" SAE ball end adjustment tool, lemme know; free to good home).

I believe most AR barrel manufacturers cut their barrels smaller in front of the gas block journals to make it easier to slide the gas blocks on without scratching the barrels. Just a guess.

 

[Alea Jacta Est]

I believe most AR barrel manufacturers cut their barrels smaller in front of the gas block journals to make it easier to slide the gas blocks on without scratching the barrels. Just a guess.

Your guesses usually ain’t…