300 BLK Info Vid - very good info.

[98Z5V]

This breaks 300 BLK down very well.  Love how they explain it all.

 

[98Z5V]

At about 22 minutes, they start describing a gas port that's too small...    Picked that up right away. 

[sketch]

Love the sub 300blk!

[MikedaddyH]

I had. Honey badger style 8' barrel one once. Couldn't get it to cycle worth poop. Gave up. Looked CAF ! Function was sub  par.  Had the pig tailed gas tube and an adjustable gas block. And a wicked brake.

Edited February 21, 2023 by MikedaddyH

[BrianK]

I love 300BLK. Did my research and built my own. It runs supers and subs, but, and here's the catch, I handload for my gun. I tried the S&B subs they mention and they just won't function the gun reliably. Supers? If a 300BLK doesn't run with supers just give up, they all do, or at least should. The fly in the ointment is if it'll also run subs as they correctly asked. But build a gun to run subs and it's probably not going to run supers the way it should. But handload and you've got it. At least that's the way I see it and that approach worked for me. Or one could try various loads until a load or loads are found that work reliably. 

If one needs a crash course in 300BLK it's found here: https://www.300blktalk.com/forum/index.php

Everything you wanted to know about 300BLK is there somewhere. Its where I got my info for what I built and I came away with the understanding that I might need to adjust the pressure curve of the ammo to make it work with subs. That's my way of saying don't ask me, instead go to that site to find and learn what you need to do for what you build. Is it worth it? They got it 100% correct that it's a niche cartridge. But on the 300blk talk forum you'll find folks who use it for all sorts of things, including  hunting. It isn't a bean field rifle, but used within it's capabilities it works fine. It didn't exist back when I was hunting, but knowing about it today I wish I'd have had it back then. 

FWIW, my 10" build is a HD gun for exactly the reasons they give. But I don't use subs for HD for at least 2 reasons. IMO they are the wrong load for indoor use. I shoot an 85 gr copper (Maker) @ 2300fps for 1k ft/lbs out of my 10" barrel. Yes, it wears a blast can but that doesn't make it quiet it just stops the pain of the eardrums from concussion. It does keep the firearm shorter. OK, why supers and not subs? A SD gun should ideally have stopping power and that begins at about (if my memory serves me) at around 2000fps. Below that the best we can hope for is that the bullet expands, dumps it's energy to produce trauma, and allow bleed out.  The worst, and here's where a sub comes in, is that a tiny hole is drilled, maybe many tiny holes, and a slowish bleed out happens. That could allow a perp plenty of time to do more evil, and stopping that was the entire purpose of deadly force in the first place. At least that's my thinking on it, with absolutely no real world experience and I hope I never get any. That's why I use Maker 85s, they have stopping power, dump a huge amount of energy, produce a perfect 3 pointed mushroom, and gel tests tell me that they'll penetrate about 6" and remain inside with no exit. If I didn't use the 85s I'd use a 110-125 grain bullet, probably a varmint bullet to make sure I got expansion if it was copper jacketed lead at the relatively low velocity we can expect from a short barreled 300BLK (2k fps or lower). IMO, there is no reason to have a long barreled, meaning 16", 300BLK. That just defeats the entire purpose of the cartridge but lots of folks have them and it's one way to get more velocity than I can never hope to get from my shorter barrel. I trade velocity to gain a smallish firearm.

OK, a bit more re: subs... There ARE bullets that expand reliably at subsonic velocity. I haven't tried them yet but they look promising. I shoot cast for subs and IMO are a no-no. Those cast bullets, and many others intended for more velocity and their tougher jackets is what I base the above comments on.

[MikedaddyH]

Looked at my notes, we did the gun to run on 125gr and 147gr rounds. The 220gr rounds did not cycle. At $26.75 and $28.99 a box back then didn't make much sense. The 125gr rounds worked pretty good so I bought a bunch of Hornady and Sierra projectiles to make it cost effective. (Later used on 308 test rounds) The gas port hole was reamed out oversized. Melted an aluminum gas block then a steel gas block . The third was an adjustable steel block that worked. If I do one again it would be a 10 inch or longer barrel.

[dpete]

220 grain commercially loaded subsonic rounds can be hit and miss as far as staying subsonic and/or functioning a rifle.  With that being said my 8" barreled SBR ate 110 grain from the get go but wouldn't cycle my 220 grain sub handloads.  Opening up the gas port on the barrel to .108 solved that issue.  I added an adjustable gas block for the option of turning down the gas when using supers.  Right now it eats everything I put into it suppressed. 

If a 300 BLK won't cycle supers there is something grossly wrong somewhere.

[shooterrex]

My 8" blackout shoots supers and subs just fine. I think the main thing is you need to be running a pistol length gas system no matter how long the barrel is.

[Sisco]

I have a commercial 16” barrel 300 Blk. With a pistol gas system and a fixed gas block that digests supers, subsonics, factory Sellors and Beloit subs and handloads of both Super and subsonics reliably. The company must have done their homework.

[Rsquared]

I built my 300 Blk 10.5" SBR using a Noveske barrel with pistol gas. It's always eaten whatever I fed it. 220 heavies, or 110 supers. It just runs. I think the only non standard part that I'm running in it is one of Slash's heavy buffers.

[Magwa]

My first SBR 300 BLK and I am still in love... 100% correct in the video Home defense does not get much better......

[BrianK]

I probably ought not be such a cheapskate and buy more commercial subsonic loads to try in mine. But as the gent in the video states it's just too expensive.