300 AAC Blackout Barrel Questions...
- Thread starter blacksky
- Start date
Barrel length doesn't really affect accuracy much between a 16.5" and 20" barrels. If you aren't using optics then the longer barrel should provide slightly better accuracy. The AAC BLK is designed around a 1:8 twist barrel, since the heavy bullets are moving so slow you need a faster twist to stabilize the bullets.
Palmetto-Pride
New member
Good luck finding a barrel longer than 16" for the 300 Black Out.
Good luck finding a barrel longer than 16" for the 300 Black Out.
http://www.tacticalammunition.com/300-AAC-Blackout-Black-Hole-Weaponry-Mid-Length-Barrel-TA88-0330.htm
16" to 24" barrels with 1-8.5, and 1-11 twist rates???
http://www.tacticalammunition.com/300-AAC-Blackout-Black-Hole-Weaponry-Rifle-Bull-Barrel-TA88-0334.htm
http://www.tacticalammunition.com/300-AAC-Blackout-Black-Hole-Weaponry-Mid-Length-Barrel-TA88-0330.htm
16" to 24" barrels with 1-8.5, and 1-11 twist rates???
http://www.tacticalammunition.com/300-AAC-Blackout-Black-Hole-Weaponry-Rifle-Bull-Barrel-TA88-0334.htm
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A 16 inch 300 BLK has as much energy as a 24 inch 5.56mm. There are velocity gains past 16 inches, not it is diminisning - Daniel Horner used a 20-22 inch:
http://bulletin.accurateshooter.com...actical-optics-divison-at-multigun-nationals/
That being said, I would go with 16 as it is the sweet spot.
http://bulletin.accurateshooter.com...actical-optics-divison-at-multigun-nationals/
That being said, I would go with 16 as it is the sweet spot.
Those choice will likely limit you to supersonic ammo, although the 1:8.5 would probably be ok. It is definitely a non-standard twist rate.
AAC recommended a 1:8 and is going to a 1:7 as noted above.
For that kind of money, you can get a barrel from Wilson Combat: http://shopwilsoncombat.com/300-AAC-Blackout/products/397/
I had to check on the twist rate and it seems to be more of a stabalization issue in SBR's than getting bullets to expand. The 220+ bullets are stabalized better at longer ranges out of a 1:7 twist in SBR barrels. From the littel I was able to research on it it seems that the 1:7 twist might not be of any benifit in a longer barrel. The SAAMI specs are still a 1:8 twist and I doubt anyone will get that changed anytime soon.
I would think that the 11-1 twist would stabilize the bullett while adding increased
So there is no advantage to a longer barrel with a 11-1 twist rate? What about a 24" barrel? I would think that the 11-1 twist would stabilize the bullett while adding increased distance to the range...
So there is no advantage to a longer barrel with a 11-1 twist rate? What about a 24" barrel? I would think that the 11-1 twist would stabilize the bullett while adding increased distance to the range...
With the .300 Blackout there isn't going to be any advantage to a longer barrel out to 24". You can't cram enough slow burning powders into the case to take advantage of the length, and fast burning powders will be used up before the bullet exits the barrel. Anything over 16-20" isn't going to gain you anything.
For example my little 6mmX47 (6-222 Rem Mag) with a 20" barrel is only 25 fps behind the Sierra manual loads out of a 26" barrel. That tells me I didn't need a 6" longer barrel as I wouldn't gain anything. So I got a lighter and better handling rifle by going with a shorter barrel.
For example my little 6mmX47 (6-222 Rem Mag) with a 20" barrel is only 25 fps behind the Sierra manual loads out of a 26" barrel. That tells me I didn't need a 6" longer barrel as I wouldn't gain anything. So I got a lighter and better handling rifle by going with a shorter barrel.
A longer barrel has more velocity. But a 16 inch 300 BLK barrel already is sucking the juice out of the cartridge as much as a 5.56mm does with a 24 inch barrel.
So if you are the type of person who wants a longer-than-24 inch 5.56mm barrel, then you would also want a longer than 16 inch 300 BLK barrel.
So if you are the type of person who wants a longer-than-24 inch 5.56mm barrel, then you would also want a longer than 16 inch 300 BLK barrel.
300 BLK does gain velocity up to and past a 30 inch barrel.
Barrel length has virtually no effect on which powder to use to get the most velocity. I know it is commonly believed to be the case, but it just does not really work that way. It does a little, but primarily whatever powder gives the most velocity in a 6 inch barrel with probably also give the most velocity in a 24 inch barrel. This is because the powder that reaches peak pressure and velocity for any given bullet weight does so within the first inch of bullet travel.
300 BLK will gain about 65 fps per inch at around 9 inches, 43 fps per inch at around 12 inches, 28 fps per inch at around 16 inches, 21 fps per inch at around 20 inches, 17 fps per inch at around 24 inches, and 12 fps per inch at around 30 inches. You just need to decide where you want to stop.
Barrel length has virtually no effect on which powder to use to get the most velocity. I know it is commonly believed to be the case, but it just does not really work that way. It does a little, but primarily whatever powder gives the most velocity in a 6 inch barrel with probably also give the most velocity in a 24 inch barrel. This is because the powder that reaches peak pressure and velocity for any given bullet weight does so within the first inch of bullet travel.
300 BLK will gain about 65 fps per inch at around 9 inches, 43 fps per inch at around 12 inches, 28 fps per inch at around 16 inches, 21 fps per inch at around 20 inches, 17 fps per inch at around 24 inches, and 12 fps per inch at around 30 inches. You just need to decide where you want to stop.
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Justice06RR
New member
1:8 is standard for 300Blackout, but damn I can't find any 16in barrels in stock. Its better to just buy a complete 300 upper instead. Somehow they are not making these barrels fast enough?
I got a lighter and better handling rifle by going with a shorter barrel
Like I said in the first post, I am blind here... So there's no difference in velocity and energy between 16" to 20" other than additional barrel weight? Will the 300AAC reach out to 300 yards with enough energy to hunt with? If so in what configuration? If not what is the max effective range?
Like I said in the first post, I am blind here... So there's no difference in velocity and energy between 16" to 20" other than additional barrel weight? Will the 300AAC reach out to 300 yards with enough energy to hunt with? If so in what configuration? If not what is the max effective range?
I would think that this round is kin to a 30-30 in performance. In other words, its more of a 200 yard deal. If you want to get out to 250+ yards with flat trajectory, a 220gr projectile may not be what you want. So, a 1:9" or 1:10" would stabilize a smaller projectile, say 150gr or 165gr.
Yes the .300 BLK will reach 300 yards, as to having enough energy to hunt with you'll have to decide.
125 grain Sierra OTM bullet
MV 2200 fps, velocity at 300 yards 1536 fps energy 656 ft-lbs.
240 grain Sierra MK bullet
MV 1000 fps, velocity at 3000 yards 922 fps energy 453 ft-lbs.
At 300 yards the 240 grain bullet would be like shooting a deer with a muzzle loader. I wouldn't hesitate to take a deer with either at 300 yards but I would prefer much closer. I do like the fact that the heavier bullet doesn't even loose 100 fps in 300 yards from the muzzle, so maybe a 165 grain bullet like the Accubond would be a great compromise, loose a little MV but pick up more energy out to 300 yards.
125 grain Sierra OTM bullet
MV 2200 fps, velocity at 300 yards 1536 fps energy 656 ft-lbs.
240 grain Sierra MK bullet
MV 1000 fps, velocity at 3000 yards 922 fps energy 453 ft-lbs.
At 300 yards the 240 grain bullet would be like shooting a deer with a muzzle loader. I wouldn't hesitate to take a deer with either at 300 yards but I would prefer much closer. I do like the fact that the heavier bullet doesn't even loose 100 fps in 300 yards from the muzzle, so maybe a 165 grain bullet like the Accubond would be a great compromise, loose a little MV but pick up more energy out to 300 yards.