New to 300BLK

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trob_205
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New to 300BLK

Post by trob_205 » Sun Jul 07, 2019 9:28 pm

Lots of good info on this sight. I guess I’d just like to run what I have set aside at the shop by everyone before purchasing and assembling for my first 300 build. It’ll be an upper for my current SBR. Building as a slight range toy with subs but mainly home/personal defense. Want it to be handy.Parts list include:

10.5” Noveske barrel, gas tube and block
BCM upper and 9” MCMR handguard
Thunderbeast CB brake. I have a TBAC ultra 7 a month or so from approval and I’m planning on getting an Ultra 5 coming as long as everything is a-ok to keep overall length to a minimum on this build.
Planning on doing a Aimpoint PRO for optic but unsure still.
Ammo will probably be a factory box offering with either 110 TSX or 110 Varmageddon for bedside based on a couple days of obsessively reading and watching YT videos (unless someone has a better suggestion). I won’t be picky on range/fun ammo as long as it’s stable and truly subsonic.

I have many springs and buffers to play with as I’m not new to ARs, but this 300 game is definitely new. I’m pretty excited for this as my feelings for years has been why stray from 556, but recent shortcomings of my 11.5” 5.56 upper has opened my eyes a bit!

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markr6754
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Re: New to 300BLK

Post by markr6754 » Tue Jul 23, 2019 11:19 pm

I’d hoped a more learned person would respond to your post... it they’re all likely out shooting. Sounds like you have a decent budget for your build...far greater than my own.

My two cents...you won’t get subsonic in the bullet weights you’re planning to use. Since you’re watching lots of YT videos, check out the 300 Blackout series by Johnny’s Reloading Bench. I don’t think he got reliably successful subsonic loads below 150gn. I can’t say it can’t happen, but you’d be in rare company.

Putting a suppressor on it, at least you can shoot quieter...but not subsonic.

Best of luck. I’m still trying to get reliable function from a 10.5” Carbine gas 300 Blackout AR. Nearly ready to swap out to a pistol gas barrel. My 8.5” pistol gas runs everything well...subs or supers...all unsuppressed.

trob_205
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Re: New to 300BLK

Post by trob_205 » Thu Jul 25, 2019 10:55 pm

markr6754 wrote:
Tue Jul 23, 2019 11:19 pm
I’d hoped a more learned person would respond to your post... it they’re all likely out shooting. Sounds like you have a decent budget for your build...far greater than my own.

My two cents...you won’t get subsonic in the bullet weights you’re planning to use. Since you’re watching lots of YT videos, check out the 300 Blackout series by Johnny’s Reloading Bench. I don’t think he got reliably successful subsonic loads below 150gn. I can’t say it can’t happen, but you’d be in rare company.

Putting a suppressor on it, at least you can shoot quieter...but not subsonic.

Best of luck. I’m still trying to get reliable function from a 10.5” Carbine gas 300 Blackout AR. Nearly ready to swap out to a pistol gas barrel. My 8.5” pistol gas runs everything well...subs or supers...all unsuppressed.
Subs and will just be for fun and won’t be picky about bullet weight. The 110s more of what it’ll be zeroed for in the HD roll. I’ve changed my mind on the can and going with a rugged micro 30 but other than that I have the rest here to get most of the upper assembled. It’ll be slow from here in out but I’m still pretty excited. I’ll check out the Johnny YT videos! Thanks!

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plant.one
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Re: New to 300BLK

Post by plant.one » Thu Jul 25, 2019 11:14 pm

couple quick rules of thumb for the black out

carbine gas firearms:

- standard carbine spring
- standard carbine buffer


pistol gas firearms:

- standard carbine spring
- h2 buffer


re: bullets and speed

light bullets - generally - are going to be used for supersonic loads. this is mostly 150gr and under and the sweet spot for most things supersonic in the blackout world is 110-125gr or so.

heavy bullets - generally - are what are going to be used for subsonic loads. usually 180-240gr class bullets, relatively easy to get to cycle in an AR with the common powders (Shooters world blackout, 1680, 4227).


now - those bullet weights are just general guidelines, a reloader there are some fun things you can do if you're willing to do your homework. but those listed above are the easy money stuff that will function in all for modes (supersonic unsuppressed, supersonic suppressed, subsonic suppressed, subsonic unsuppressed).


hth
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dellet
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Re: New to 300BLK

Post by dellet » Fri Jul 26, 2019 11:47 am

plant.one wrote:
Thu Jul 25, 2019 11:14 pm
couple quick rules of thumb for the black out

carbine gas firearms:

- standard carbine spring
- standard carbine buffer


pistol gas firearms:

- standard carbine spring
- h2 buffer


re: bullets and speed

light bullets - generally - are going to be used for supersonic loads. this is mostly 150gr and under and the sweet spot for most things supersonic in the blackout world is 110-125gr or so.

heavy bullets - generally - are what are going to be used for subsonic loads. usually 180-240gr class bullets, relatively easy to get to cycle in an AR with the common powders (Shooters world blackout, 1680, 4227).


now - those bullet weights are just general guidelines, a reloader there are some fun things you can do if you're willing to do your homework. but those listed above are the easy money stuff that will function in all for modes (supersonic unsuppressed, supersonic suppressed, subsonic suppressed, subsonic unsuppressed).


hth
Probably some of the best advice you can get is right there.

Set it up correctly, confirm function with known good loads or factory ammo, then start playing with the fun stuff.

The only thing I would add is that the system really was never designed or intended to function subsonic with bullets less than 200 grains.

It doesn't mean you can't get 110's to cycle an SBR at subsonic speeds, it's just not practical.
300 Blackout, not just for sub-sonics.

trob_205
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Re: New to 300BLK

Post by trob_205 » Sat Jul 27, 2019 11:25 am

That’ll be my plan then. I’ll stick to box ammo for now 110’s for supers and I’ll play around with different sub loads and won’t mess with anything other than 200+. Subs will more or less just be range fun and for wow factor. The Rugged Micro 30 is adaptable. It’ll be in 5” configuration bedside and around the house but when playing around with subs I’ll add the extra baffle adapter and make it as quiet as possible. And probably end up with a light and handy 300BLK bolt gun for true wow factor but that’s down the road.

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Gman2017
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Re: New to 300BLK

Post by Gman2017 » Sat Jul 27, 2019 5:14 pm

Welcome to the forum.

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Re: New to 300BLK

Post by Dolomite_Supafly » Sun Jul 28, 2019 6:27 am

If you are going to be shooting a lot of both supersonic and subsonic you might want to invest in an adjustable gas block. Yes an upper can be made to function with both but there are compromises that can be addressed with an adjustable gas block.
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trob_205
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Re: New to 300BLK

Post by trob_205 » Tue Jul 30, 2019 4:46 pm

Dolomite_Supafly wrote:
Sun Jul 28, 2019 6:27 am
If you are going to be shooting a lot of both supersonic and subsonic you might want to invest in an adjustable gas block. Yes an upper can be made to function with both but there are compromises that can be addressed with an adjustable gas block.
This setup will be primarily used in a home defense roll with supers and subs will just be for fun at the range. It’ll be set up with whatever spring/buffer works best for whichever supersonic HD load I choose.

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plant.one
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Re: New to 300BLK

Post by plant.one » Tue Jul 30, 2019 10:41 pm

trob_205 wrote:
Tue Jul 30, 2019 4:46 pm
Dolomite_Supafly wrote:
Sun Jul 28, 2019 6:27 am
If you are going to be shooting a lot of both supersonic and subsonic you might want to invest in an adjustable gas block. Yes an upper can be made to function with both but there are compromises that can be addressed with an adjustable gas block.
This setup will be primarily used in a home defense roll with supers and subs will just be for fun at the range. It’ll be set up with whatever spring/buffer works best for whichever supersonic HD load I choose.
since you're discussing a PD/HD scenario, you're going to want to hedge on reliability. that being i would probably go with the standard h2/standard carbine spring formula. unless your gas port is grossly oversize - which i dont seem to recall being a noveske problem.

tweaking a recreational gun for performance vs tuning a defense weapon for defense are often two very different strategies.

which very much makes DS's option of an AGB kind of the best of both worlds - if you feel you must tinker anyway. You can tone things down for a day at the range, or a session suppressed, yet still be able to take a few clicks back to "normal" for things that go bump in the night without having to take the gun apart to tune it.
Reloading info shared is based on experiences w/ my guns. Be safe and work up your loads from published data. Web data may not be accurate/safe.
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