View Full Version : Ideal 300 Blackout Barrel Length for HD Pistol that will eventually be Suppressed?
MeanStreaker
06-17-16, 10:27
I'm building my first .300 blackout... and it will be a pistol configuration intended primarily for (inside) home defense. Other than fun plinking and a lot of training, it could be pressed into service outside checking on a bump in the night around our five acres, but I'd likely grab another carbine if I knew I were heading outside.
Eventually it will be suppressed, but that will come later.
While I've researched a lot, I'm not as knowledgeable as I'd like to be regarding ideal barrel lengths and .300 ballistics for this purpose, also considering added length of a suppressor someday inside a tight hallway.
To put my biases on the table, I'm strongly leaning towards a BCM 9" unless someone can talk me out of it with data I'm ignorant about.
Thanks!
I'm building my first .300 blackout... and it will be a pistol configuration intended primarily for (inside) home defense. Other than fun plinking and a lot of training, it could be pressed into service outside checking on a bump in the night around our five acres, but I'd likely grab another carbine if I knew I were heading outside.
Eventually it will be suppressed, but that will come later.
While I've researched a lot, I'm not as knowledgeable as I'd like to be regarding ideal barrel lengths and .300 ballistics for this purpose, also considering added length of a suppressor someday inside a tight hallway.
To put my biases on the table, I'm strongly leaning towards a BCM 9" unless someone can talk me out of it with data I'm ignorant about.
Thanks!
BCM 9" is good. Noveske makes an 8.5" (used to be an 8.2"), Ballistic Advantage makes something in that range as well. Some good options in the 8"-9" range.
Im happy with my 9 inch aac upper
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waffentomas
06-17-16, 19:58
I went with a 12". Since I hand load, I wanted the versatility of a slightly longer barrel. The longer dwell time allows me to use slightly slower burning powders and heavy bullets. I have more options to adjust powder levels and velocity. Plus, muzzle flash can be manipulated as well.
CanineCombatives
06-19-16, 15:09
8", 8.5" and 9"
ExplorinInTheWoods
06-24-16, 15:32
What length will your suppressor be? If you're getting a 7-8 inch suppressor try going shorter on the barrel like noveske 8.5
IMO, anywhere from 7.5" to 9" is be fine, with a preference toward the shorter end.
I use a 1:7 twist 8 inch barrel from law guns. Works well
I dont know if AAC is making uppers anymore so if I was going to buy an upper it would be a KAC, BCM, or Noveske which will all be around 9" or over. I personally see no need to go over 9" At the end of the day the minimum barrel length will be determined by the warranty of your suppressor. Most suppressors warranty 8-9". The AAC SDN6 which I would not recommend buying except for a few specific use cases warranty is for 7.5"
So I know it's at the back of the list but if you want to go short you need to put some thought into what suppressor you want to use.
The easy purchase is a BCM 9" upper. I dont have any personal experience with them but the 4 that I know for sure that will function all four ways is AAC, BCM, KAC, and Noveske. A lot of barrel makes do no R&D and think it's all good with a 1in8 barrel that does not have the proper gas port. I would only buy a 1in7 twist and make sure it runs all four ways - suppressed/subs, suppressed/supers, unsuppressed/subs, unsuppressed/supers. If you are going custom I would go a 1in6 twist if going under 9".
backpacker
06-26-16, 13:14
8" noveske barrel if you build your own upper.
Otherwise just buy a factory BCM 9" upper. Great uppers and come with BCG for like $700.
I'm not a fan of AR pistols at all, but if this was a SBR, I would inquire as to what ammunition is intended for use. Many like the Barnes black tip, or a variant there of for supers. Some look at boutique subs, that can make a big difference in the end for item selections.
I'm not a fan of AR pistols at all, but if this was a SBR, I would inquire as to what ammunition is intended for use. Many like the Barnes black tip, or a variant there of for supers. Some look at boutique subs, that can make a big difference in the end for item selections.
This should have no impact in a properly configured blackout upper other than loss of velocity as the barrel gets shorter.
I would not tend to agree with that statement as a "total" rule, too many variables. I do agree that a 9"ish upper plus/minus 2" may suit many well, that does not automatically mean that it would suit all well.
I may have a less than 4" upper with a fixed spacer Ti-Rant full size .45 that works well with a limited firing schedule for use with some of these subsonics.
I may have a 14.5" carbine gassed suppressed only that will not cycle any subsonics by design intent.
Does that reduce their intended merit for their intended use? It's almost like asking what barrel length for a 5.56 AR, it just depends really. It's no different in concept in 300 Blackout, only that the Blackout envelopes a wider span.
I completely understand your point but for the sake of the OP's question, in my mind those are purpose built rigs that by their nature cannot function all four ways. I have one that will only run suppressed (subs & Supers) but it was custom built that way.
The cartridge was designed to function all four ways and as a general rule unless being a purpose built rig (such as your examples) it should function all four ways.
Anyone buying an off the shelf upper (unless specified as a purpose built rig) that does not function suppressed/subs, suppressed/supers, unsuppressed/subs, unsuppressed/supers is not getting the full potential of 300 blackout and getting screwed by builders that dont understand the cartridge and just throw together some 556 knowledge along with what's in the SAAMI spec for 300.
Can you tell I am a little bitter about this. Spend some time over at 300blktalk.com and you will see all the crap that builders and barrel makers have put out that just dosen't work. It gives the cartridge a bad name.
It really applies to a product that suits the end use for the balance of their intended operation. All 4 modes may not be as much of a concern as other areas. It really just depends on end use of the product, a product that suits the users better than the others.
The 5.56 AR and the 300 Blackout AR are not identical animals, they each have their own specific traits that can be tailored for many different end uses.
Tagged for interest. Trying to decide between 9" and 12.5" (BCM offerings). It's going to be a while though, I need to wait until my form 1 comes back approved.......next year.......sigh.
Tagged for interest. Trying to decide between 9" and 12.5" (BCM offerings). It's going to be a while though, I need to wait until my form 1 comes back approved.......next year.......sigh.
What are you looking to use it for?
Range use, hog hunting eventually. I plan to reload for it. It will be run suppressed all the time.
Range use, hog hunting eventually. I plan to reload for it. It will be run suppressed all the time.
I would generally tell you to only go 9" and under but if you are going to use it for hog hunting a lot the 12.5 will give you a bit more velocity. The 9" BCM is very handy rifle.
You going to throw a can on it?
Yes, sure fire 7.62 socom mini. Sounds like 12.5 would be the way to go for hogs.
Nice that it is with a shorter can so going 12" is not really a big issue. Here is a link to the velocity data - http://www.300blktalk.com/forum/viewtopic.php?t=98165
Excellent. BCM doesn't have the 12.5 in stock right now, but that looks like what I will get when it is back in stock. Thanks again.
Nice that it is with a shorter can so going 12" is not really a big issue. Here is a link to the velocity data - http://www.300blktalk.com/forum/viewtopic.php?t=98165
If I am shooting subsonic loadings suppressed, why would a longer barrel be more advantageous for a hunting set up? A little longer range perhaps? That would have more to do with velocity correct? I suppose supersonic loads suppressed from a longer barrel would be more ideal for a hunting setup.
The only advantage to a longer barrel is higher velocity. If you're shooting subsonic you generally don't want higher velocity because you want to keep the round subsonic. If you're hunting using supersonic then you would want higher velocity and a 12 inch barrel would be preferable to a 9 inch.
backpacker
07-15-16, 13:52
When it comes to .223 then yes barrel length can add a significant velocity change require for expansion/fragment, however, with blackout this is not necessary. The Barnes 110 TAC-TX and other similar bullets expand and are effective out of a 9" barrel and there is no reason to go longer even for hunting. The ONLY reason to get a 12" BLK barrel instead of 9" is for additional accuracy. The 9" is what I use and is accurate and effective, however, my friend has a 12" Noveske barrel and MY GOD that thing is a tack driver. He consistently is under 1moa and that is impressive for a semi auto BLK. My 9" could never compete with that accuracy. But, for me I'm happy with 2.5 MOA and a 9" upper.
The ONLY reason to get a 12" BLK barrel instead of 9" is for additional accuracy.
There is no correlation between barrel length and accuracy.
backpacker
07-15-16, 13:58
Honestly you can't go wrong with a factory BCM 9" upper. I have almost every upper and rifle you can imagine and EVERY time I go out I take my 9" BCM BLK. It's all around good at everything under 200 yards for me. It's good with subs and supers for hunting and home defense.
backpacker
07-15-16, 14:00
There is no correlation between barrel length and accuracy.
I have heard that, but personally between from what i have the 12" Noveske is by far the most accurate.
That's comparing my: Noveske 8", BCM 9", AAC 9", Daniel Defense 10" (all in BLK) all are less accurate than that 12" Noveske.
But all are acceptable for sure.
backpacker
07-15-16, 14:10
Plus, a 9" with PDW stock fits great in a backpack making hiking around easy. Light, small, yet effective at distance.
That's compared to an 11.5" 556 upper with TREKt. The 12" plus can would be longer than that.
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