300 blk?

A lot of people have cycling problems with their 300 Blk, more so than with most other AR calibers. Best advice is to go with a Pistol length gas system, regardless of barrel length you choose. Also, to add flexibility, I used an adjustable gas block so you can get the gas just right for supersonics and subsonics. I've got mine tuned to run both with no problems.

If you ONLY plan to shoot supersonics, then carbine gas length is OK.

Some people have feed problems due to using reloaded ammo, which doesn't use a 300 Blk friendly profile for use in standard AR mags. Factory ammo uses a bullet with a profile that the ribs in the mag don't interfere with the round. I lightly sanded down the side ribs on 2 mags, and don't have any problems with my reloads.

I like mine, but they are much more finicky than say a 6.8 SPC (which I also have, and which is more powerful and more accurate). 300 blackout uses pistol powders (H110, Lilgun, 296), so if you reload any of the magnums, you probably already have some. A lot of people (myself included) tend to get much higher extreme spread in velocity than with other calibers I reload. With 300, lucky to hold 80fps in a 10 shot group. Other rifle calibers I load are 1/2 that or less.

Brass is pretty easy to cut down and make from 5.56 brass. I've done about 300 pieces.

It is fun to tinker with, I went with a 8.5" barrel and made a pistol until I get my SBR stamp back for it.

It seems to me that .300 works best in the following niches:

1. SBR with barrel under 11"
2. Suppressed using supersonic and subsonic
3. You want a 7.62x39 type cartridge but in an AR platform

I am thinking with the current panic mode going on right now, unless you already load for .223 and have components, I would NOT get into .300 Blackout.

Said another way, if you rely soley on .300 Blackout ammo to get shipped to you, you might be SOL.

Well there is a forum dedicated to it and apparently it is a wash for a 16" BBL (and I'm thinking carbine is better for a dual supersonic/subsonic gun). I plan to build a dual use 300 Recce and am leaning toward 16" 1:8, carbine buffer, and carbine gas length (I have a very long 7.62 silencer that I use for everything from 5.56 to 7.62). Wilson Combat BBL a good choice?

One of these days I will get around to SBRing a lower.

Mike

I have two 300 BLK ARs, a 16" and an 18". The only major cycling problems I have had has been with heavy bullets shooting them un-supressed. Also, the 18" rifle does not always lock the bolt open on the last round in the magazine.

I like 125 (Speer 125 TNT) and 155 (Hornady 155 AMAX) grain bullets. I currently have H1 buffers in both.

I feel the 300 BLK is a dandy 100 yard home defense rifle.

A short muzzle device on the 16" barrel gun makes it quite handy without getting into SBR paperwork.

I converted one of my ARs to .300 Blackout, using a SOTA 16" barrel with a carbine-length gas system.

I'm amazed at how sweet it shoots. Easily shooting under 1" groups @ 100 yds.

I also load my own and don't have any problems with my reloads' cycling, either. I am using an adjustable gas block.

.300 Blackout is just a novelty for me. I thought at first that I might load some for sale, but they're just too labor-intensive for my business. Friend of mine does sell .300 Blackout and is selling 20k weekly to Brownells alone.

Young Marine was at the range the other day when I was shooting my .300 Blackout. He said that his unit was changing over to .300 Blackout when he mustered out. Don't know if he was telling the truth or not, but I do know that SEALS use .300 Blackout for ranges out to 150 meters.

Won't be getting the tax stamp for my suppressor for the Blackout for 8-9 more months.

I thought I wanted a 300 blk, but not being a reloader, an AR in 7.62x39 makes more sense to me, as subsonic and/or SBR doesn't really interest me (for this particular platform, not overall). Less than .25 per shot makes MUCH more sense to me than paying over $1 for the same ballistics. Granted, I haven't made the leap yet, and don't know that I actually will, but, for your neeeds, the x39 seems to make at least as much sense as the 300

It does well to 150 yards supersonic

It does well suppressed subsonic

If you already have a 223 to convert its a no brainer

As stated, if you reload, you can convert 223 brass to 300 blk
And have a cheap plinking round

If you continue to shoot 300blk and 223, you need to mark the mags.

Kabooms have already been documented with wrong ammo, wrong gun

If you dont reload, you are in a pickle, because the much hyped, low cost ammo is not available, and hasnt been for many months

Some people claim it to be a 300 yards gun...... Its not

There are much better choices for out to 300 plus yards, especially if you hunt

I am also amazed that one of the 300 blk founders has the ability and time to troll EVERY forum in north America touting the 300.

Much arguing........


Its a good option. No reason to trash every other caliber made.

For me, as a hunter, I researched the heck out of the 6.8 and 300blk, I compared the best
Bullet I could find from the 300BLK and the best bullets for the 6.8.

Using the common hunting rule of thumb for minimum ft/lbs of 1000, I found the best bullet of
The 300 blk dropped below 1000ft lbs at 128 yards.

The bullet I hunt with, the Hornady 120 SST 6.8 drops below 1000 ft/lbs at 274 yards.

A little over double the distance, if you use this rule of thumb.

I chose the 6.8

However

If I didnt hunt, AND reloaded the 300 BLK would be a great choice for plinking
As the 223 brass is literally laying on outdoor ranges everywhere.
(I picked up at least 100 pcs this weekend)

The 6.8 brass is a 30 cents to 55 cents apiece

I may be looking at the 300 blk in the future

i have no problems cycling my pistol length gas system with 8 inch barrel shooting supersonic and subsonic up to 208 grains. i havent tried any heavier bullets yet though.

i also have not shot it suppressed yet, but if it cycles subs unsuppressed, it should have no problems doing it with the higher back pressure condition created by a can.

I'm trying to get into it now; I have the gun put together and looking for ammo. Loaded ammo is still out of stock; I've been able to find bullets and brass... still need powder.

From what I can tell it has all the range you will ever need out of a carbine, though it does probably give up a slight bit to 5.56. Advantages over 5.56 are numerous however:

-Better optimized for short barrels
-Suppresses better
-Hits harder up close

As an AR shooter of 12+ years now I've looked at ever new cartridge, and Russian cartridge that has come down the pipe... 6.8, 6.5, x39, 5.45... probably others... 300blk is the first one that has ever made me pull the trigger.

Its versatility in loads, short barrel optimization, and compatibility with super common 5.56 and .308 parts and components is pretty awesome, in my opinion.

As an AR shooter of 12+ years now I've looked at ever new cartridge, and Russian cartridge that has come down the pipe... 6.8, 6.5, x39, 5.45... probably others... 300blk is the first one that has ever made me pull the trigger.

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Same here. I pulled the trigger on a .300 BLK build even though factory loaded ammo is darn near impossible to come by at a decent price now. The ability to hit like a 16" 5.56 but from a 9" barrel plus the whole added bonus of having a subsonic cartridge with a great BC with just a change of the mag? I hope it lives up to the hype!

Same here. I pulled the trigger on a .300 BLK build even though factory loaded ammo is darn near impossible to come by at a decent price now. The ability to hit like a 16" 5.56 but from a 9" barrel plus the whole added bonus of having a subsonic cartridge with a great BC with just a change of the mag? I hope it lives up to the hype!
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Bartholomew: I don't quite understand your next-to-last sentence. The only change is the barrel; same mags, bolt, etc., are used with .300 Blackout as with 5.56/.223.

I don't buy into the 1000 lbs/ft "rule of thumb." Lots of Bambis killed with 500+ lbs/ft projectiles!! Most of the deer hunting around where I live is done at distances under 100 yds, for which .300 Blackout supersonic would be fine. I clocked some of my 168gr bullets @ 1900+fps.

hentown said:

Bartholomew: I don't quite understand your next-to-last sentence. The only change is the barrel; same mags, bolt, etc., are used with .300 Blackout as with 5.56/.223.

I don't buy into the 1000 lbs/ft "rule of thumb." Lots of Bambis killed with 500+ lbs/ft projectiles!! Most of the deer hunting around where I live is done at distances under 100 yds, for which .300 Blackout supersonic would be fine. I clocked some of my 168gr bullets @ 1900+fps.

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There are good bullets for the 300 that do fine at the distance you are talking about.



Many hunters choose 1000 ft /lbs is for a quick ethical kill on deer size game.....I think the Texas boar are tougher to kill than deer, so for me, I wouldnt do a shot that would give me 700 ft/lbs let alone 500 ft/lbs.

Some of the land I hunt on opens up where a 250 yard or more shot could occur. The factory load 120SST Is in the mid 950ft/lbs range at 300 yards (I load it a bit hotter)

You could probably kill deer with a handgun at even 200 ft/lbs or less for a close in shot, but, it may be a slow and painful death for the animal

Bartholomew: I don't quite understand your next-to-last sentence. The only change is the barrel; same mags, bolt, etc., are used with .300 Blackout as with 5.56/.223.

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He's saying he can go from supersonic 300blk to subsonic 300 blk by changing mags

Walkalong said:

The hashmarks on the 3X are for a .223 trajectory, and are not particularly useful for .300 BLK, if that is what you mean.

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ID-shooting said:

wondering just how far off they were. Not sure I would use one in this application though.

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Go on Nikon's website and look at their spot on calculator. you can choose what ever load you are using and play with sightin range and it'll tell you exactly what range the hash marks are.
I find with this it's a wonderful scope for this application.

What Mavracer said... plus I was noting that a Hornady 110gr VMAX out of a 9" barrel (if you believe the muzzle velocity numbers) has the same muzzle energy as a Hornady 75gr BTHP out of a 16" barrel and is quite impressive in gel as well. For the typical ranges a rifle gets used at, it is similar (or arguably better) punch in a more compact package.

He's saying he can go from supersonic 300blk to subsonic 300 blk by changing mags

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Thanks. That makes perfect sense. My observation about lbs/ft required for a so-called clean kill were based on the fact that so many deer are killed at 30-50 yds with handguns, many of which don't sport 500 lbs/feet at point of impact.

I don't care for deer hunting; just not much of a sport for me, so that use for the .300 Blackout is moot for me.

I'll probably stockpile 1000-or-so rounds, just in case I "need" them.