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Thread: Black Hole Weaponry Barrel Review - 308 Build

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    Black Hole Weaponry Barrel Review - 308 Build

    Well... freaking finally I was able to complete my 308 build and put some time in to finish my review.

    Accuracy Groups - For accuracy testing, I reached into my stash of Hornady ammo and luckily I had a few boxes of Hornady’s 150 gr SST, 150 gr SST Superformance, 168 gr A-MAX Superformance Match and 178 GR BTHP Match. From my experience, Hornady ammo has delivered outstanding and these results continued that legacy.


    My best 5-shot 100 yard group was with the Hornady 150gr SST .456” group which from perspective is outstanding for a semi-auto 308 firearm. As you would expect at longer distances in the 200+ ranges, heavier bullets start to gain an advantage. By the time I was reaching out to the 300 yard line the 168gr rounds were my favorite round with tighter groups.

    Using my iStrelok ballistic iPhone app to dial in with a very light breeze, my personal best 300-yard group shot from prone from the Atlas bipod was with the 168gr A-Max Superformance Match which delivered a 2.17” group at 300 yards. What was surprising was that as long I did my part, I kept my other two groups under 2.25". I was thrilled with these initial groups, but most interesting to me was how the groups held together at those longer ranges and that the most accurate round at 100-yards was not the most accurate at 300-yards. To give you some perspective my old DPMS 308B best 300-yard group was just under 4" which is not bad at all, but not in the same class at this barrel.

    I know shooting off sandbags or locking into a LeadSled would immediately minimize the human variable and decrease groups. Additionally with a bit more work on understanding how this rifle shoots long-term and a little reloading bench load tuning I have no doubt sub-2" 300-yard groups are possible off the Atlas bipod. At this point I have not pushed the rifle beyond the 300-yard range, however once I work through a few Sierra and Hornady reloads, you can bet I will see what this rifle can do out there near the 1/3 mile marker. Based on conversations with a few tremendous distance shooters, I believe this build could easily deliver accurate shots out at 1000 yards. At those distances I have a whole lot of work still to do on my side to reach out that far.

    Average 5-shot 100-yard groups
    Hornady 308 Win 150 gr SST
    Best 5-shot 100-yard Group .456” - 5-Group Average .743”

    Hornady 308 Win 150 gr SST Superformance
    Best 5-shot 100-yard Group .593” - 5-Group Average .789”

    Hornady 308 Win 168 gr A-MAX Superformance Match
    Best 5-shot 100-yard Group .478” - 5-Group Average .692”

    Hornady 308 WIN 178 GR BTHP Match
    Best 5-shot 100-yard Group .494” - 5-Group Average .710”

    I doubt you will here many other writers admit this, but to be totally honest this rifle's accuracy far exceeds my ability to shoot it. It can deliver .5" 100-yard groups all day long in my hands and in the hands of someone really good could probably deliver near single hole groups. The same goes for those longer distances where an I am delivering just over 2" groups. Perhaps later this year I will have an opportunity to put this in the hands of a military shooter who I know can wring out the accuracy of this barrel.

    Full review here
    Black Hole Weaponry 308 Barrel Review
    Attached Images Attached Images
    Last edited by majorpandemic; 04-12-2013 at 06:23 PM.
    No my name is not Pandemic, nor am I a Major, I am but a mortal being, using my freedom, intelligence, and available resources provided in this great free nation to survive another day.

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    I have 2 5.56 AR's with BHW barrels 1-8 poly 3 twist, they both shoot great. What twist rate and barrel length did you go with?
    "Better to have and not need than need and not have"

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    1:11 Twist - I also have two of the .223 Wylde barrels which are both extremely accurate.
    No my name is not Pandemic, nor am I a Major, I am but a mortal being, using my freedom, intelligence, and available resources provided in this great free nation to survive another day.

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    1-11 is good for 168's. I've been doing some research and I am going to go with 1-8 twist for my next 30cal barrel. It will stabilize just about any bullet, and the faster twist allows for greater velocity with less powder. That should lead to longer barrel life as well.
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    I've been using one of the 16" Rainier Select barrels on a 308 build for about a year now. I tend to run heavier bullets with the 308, and have found that the 1:11 twist on the Rainier (made by Black Hole Weaponry) is able to stabilize up to 190 grains at least. Accuracy at 100 yards is not stellar, at about 1.5 moa, but by the time it reaches 200 yards it seems to be in a stable trajectory as the groups at that distance only open up slightly to around 1.75 to 2 inches. I've been able to push the 190's out to 1000 yards with pretty good consistency using a charge of 43 grains of Hodgedon CFE-223.

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    Quote Originally Posted by Razor74 View Post
    1-11 is good for 168's. I've been doing some research and I am going to go with 1-8 twist for my next 30cal barrel. It will stabilize just about any bullet, and the faster twist allows for greater velocity with less powder. That should lead to longer barrel life as well.
    Where did you get this info? I was told the exact opposite by Krieger. High twist equals more drag and lower velocity. They reccomended a 1-12 twist for 168's and they told me it would increase velocity and have less drag in the barrel. I went with a 1-11.25 for my barrel because I wanted to have the option to go a little bit heavier. I would think a 1-10 would be plenty for a .308 even with the heaviest bullets.
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    The only reason I would get a 1-8 twist in a 308 is if I wanted to stabilize subsonic a. 1-10 is about all you could ever want or need and will stabilize 220's easily which is probably more bullet than your lookin for anyways.

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    You are correct a 1-10 is a good twist and is fine for most 308's. But the 1-8 does give you more options it will stabilize a wider range of projectiles. We as shooters tend to stick the norm and not want to challenge conventional wisdom. Years ago 1-12 was the popular twist then 1-11.25, 1-11 now 1-10, can you see the trend here. As bullet tech advances we get heavier bullets with better BC that stabilize better and farther. Think of a football we all know that the tighter the spin the faster and further the ball will go, the same applies to bullets. Desert tactical arms uses 1-8 twist in their Covert rifles with a 16" barrel and they are consistently going out to 1K and farther. If more spin equals more drag how do you explain there success. If you have the time pick up the latest issue of SNIPER magazine there is a really good article in there about this very subject.
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    Faster spin equals more stabilzation for heavier bullets, it does not get you more velocity. Tighter twist = more drag in the barrel. Heavier bullets will stay supersonic longer but they are not going faster becuase of a tighter twist.
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    As I said in my last post, if you can use a shorter barrel 16" and get almost the same velocity as a 20-22" barrel, then logic says that in some part a faster twist does translate to faster velocity. I didn't want to have a really long post with a lot of techno jargan so please when you get time go to your local book store and read the article on page 68 in latest SNIPER magazine. The longer a bullet stays stable the more FPS it retains, so yes you are in part correct the tight twist may not generate more FPS it helps to retain it. Sorry I was not more clear before. 1-8 5R or Poly twist would be optimal to me for this as they have been said to produce less drag.
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    Well I'm not claiming to be an expert on this subject, but I'm going off information I received from a well known barrel maker not a "SNIPER" magazine. Not trying to come off as a smart ass but it's just not true what you are claiming. You will never get more velocity out a 16" barrel then you will out of 24". Can you sling lead out to 1k with a 16" barrel sure is a 1:8 twist going to increase accuracy I'm sure that's highly debatable.
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    I never stated that you could get more velocity from a 16" barrel than 24" I said that they were close to 20-22" barrels, not more. There is a reason that there so many different barrel makers and twist because there are different philosophies about both. I'm not saying that 1-8 is the end all beat all twist for every one and every situation, I'm just speaking from my experience and the experience of a person that has been testing this for the military with very favorable results. If all you want to do is punch paper at 100yds to see how tight you can get a 5 shot group, then 1-8 may not be the best twist for you. But if you are like me and many others that are trying to push the envelope with longer heavier bullets this is a twist to do that. I am not an expert by no means myself, and I did not think that you were being a smart ass and I hope you didn't think I was trying to be either. Just putting some food for thought out there. If we stop questioning conventional wisdom with new ideas we will never grow as shooters or people.
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    By the way just to clear the air. As far as " SNIPER" magazine goes the majority of the writers in this magazine are highly trained snipers, So they are writing from their experience. If you have never checked it out do so there is some really good info in it.
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    Quote Originally Posted by Razor74 View Post
    By the way just to clear the air. As far as " SNIPER" magazine goes the majority of the writers in this magazine are highly trained snipers, So they are writing from their experience. If you have never checked it out do so there is some really good info in it.
    Actually this raised a really good question for me. The current issue of Sniper (I think that was the mag), had an article on twist specifically centered around the 308 and they said they their testing showed that a faster twist netted better accuracy at longer and longer distances and also less drag. Makes me want to test out that theory. These are about the best groups I have ever shot at 300 yards, so before I go buying another barrel, I need to make sure I can shoot this one well enough to get me under the 2" group consistently at 300. Black Hole said I should be in the 1.5" group range at that distance with this 18" barrel.
    No my name is not Pandemic, nor am I a Major, I am but a mortal being, using my freedom, intelligence, and available resources provided in this great free nation to survive another day.

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    My take-away from reading that article was that the tighter twist rate barrels impart a greater amount of gyroscopic stability on the bullet for a given muzzle velocity. The tighter twist may in fact lead to a slightly slower muzzle velocity, but the bullet will have greater stability to overcome the destabilizing effects of transition into a subsonic trajectory, thus having a much longer effective range than an identical bullet fired from a slower twist rifle. This essentially turns your 308 bullet into a 300 Blackout Sub at the point where it goes subsonic. Figure on an additional 200 to 300 yards of effective range (Maybe more if you are Todd Hodnett) if you have the ballistics calculated correctly.

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    Quote Originally Posted by Raptorx View Post
    Where did you get this info? I was told the exact opposite by Krieger. High twist equals more drag and lower velocity. They reccomended a 1-12 twist for 168's and they told me it would increase velocity and have less drag in the barrel. I went with a 1-11.25 for my barrel because I wanted to have the option to go a little bit heavier. I would think a 1-10 would be plenty for a .308 even with the heaviest bullets.
    I have to go with Raptorx on this one. A few years back, I was building a .308 bolt gun just for the express purpose of shooting out to 1000 yards. I selected the 175 grain Matchking as my bullet and gave Krieger a call about a barrel. The guy I talked to suggested a 1-12 barrel for my purpose and I ordered one. It shoots the 175 grain magnificently. I think 1-10 is the fastest I'd ever use in a .308. It should easily handle a 190 grain bullet which is heavier than what I'd use anyway.
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    Optimal twist rate is dependent on projectile bearing surface. The rifling does not care what weight the bullet is, only how much of it can be engraved. Longer bearing surfaces don't do well in loose twists.

    With a lot of the target bullets, as the weight gets heavier, the bullet bearing surface also increases, but secant ogives and long boat tails cut into this length as well.

    The next issue has already been mentioned, which is gyroscopic stability. Since many of us are interested in long-range performance, we want the projectile to spin faster at distance to maintain stability. There are charts and programs to compute your stability factor with a certain twist rate, bullet type, and barrel length.

    There is a corresponding relationship between spin stability, twist rate, bearing surface, and barrel length, which is why DTA uses a tighter twist on the 16" covert. To get an equivalent bullet to spin well at 800-1200yds from a shorter barrel, you need a tighter twist because you're starting with slower speed.

    A tighter twist then has implications for internal ballistics, because start pressure changes. Now that the twist is tighter, the projectile needs more force to drive it into the lands, generating more peak pressure compared to an equivalent charge with the same bullet in a looser twist.

    There does seem to be merit with the shorter bull barrel and tighter twist, which Todd Hodnett has been getting unusual results with in both .308 16" barrels and .338 LM 20" barrels. If you follow what he's been doing, he has experienced better long-range accuracy with the short, tight twist bull barrels well past 1000yds.

    So I actually do think there might be some merit to the experimentation with a 1/8 twist in the .308 16" with 175's. Todd was pushing to keep the bullet spinning consistently as it passes through the transonic barrier, and his results seem to indicate that he achieved that in spades, especially when a tight twist 20" .338 TRG is grouping better than a 29" at 1 mile. Very few shooters actually have the skill and experience to do any type of conclusive testing at those distances, but as long-range shooting becomes more popular, I think these numbers will grow.

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    Quote Originally Posted by Razor74 View Post
    You are correct a 1-10 is a good twist and is fine for most 308's. But the 1-8 does give you more options it will stabilize a wider range of projectiles. We as shooters tend to stick the norm and not want to challenge conventional wisdom. Years ago 1-12 was the popular twist then 1-11.25, 1-11 now 1-10, can you see the trend here. As bullet tech advances we get heavier bullets with better BC that stabilize better and farther. Think of a football we all know that the tighter the spin the faster and further the ball will go, the same applies to bullets. Desert tactical arms uses 1-8 twist in their Covert rifles with a 16" barrel and they are consistently going out to 1K and farther. If more spin equals more drag how do you explain there success. If you have the time pick up the latest issue of SNIPER magazine there is a really good article in there about this very subject.
    Dta is using 1/8 twist in 308 16" barrels. That is due to the velocity being lower out of the short barrel. That does not mean 1/8 is better for all 308 barrels. Shooting heavy bullets out of short barrels with fast twists is not the way to get to 1k yards. Sure, it can be done but that's not the best tool for the job. Really fast twist rates may work, but are not ideal. Most typical 308 barrel lengths a 1/10 is more than enough for even the heaviest bullets you would use in that cartridge.
    Another example is Bill Alexander uses a faster twist in his shorter barrel grendels but the long ones get a slower twist.
    Velocity is a factor when determining twist rate and bullet stability but is not necessarily the result of twist rate.

    Read this article
    http://www.jbmballistics.com/ballist...tability_2.pdf

    In short. 1.3-2.0 factor is ideal. Bench rest shooters try to be closer to 1.3. Military will go as high as 2.5 to be safe in cold weather.

    And play with this bullet stability factor calculator.
    JBM - Calculations - Stability

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    As I said in my last post, if you can use a shorter barrel 16" and get almost the same velocity as a 20-22" barrel, then logic says that in some part a faster twist does translate to faster velocity. I didn't want to have a really long post with a lot of techno jargan so please when you get time go to your local book store and read the article on page 68 in latest SNIPER magazine. The longer a bullet stays stable the more FPS it retains, so yes you are in part correct the tight twist may not generate more FPS it helps to retain it. Sorry I was not more clear before. 1-8 5R or Poly twist would be optimal to me for this as they have been said to produce less drag.

    I read the article and I have read other articles talking about fatser twist rate for long range shooting LONGER bullets, like LRRP said above it isn't the weight that matters, it's the length. I recently had a 300WM built by Bugholes here and actually ordered it with a 1:8 5R. I plan on shooting 208gr, 210gr and 220gr with it. Unfortunately I just got it a couple months ago and haven't had a chance to shoot it with the weather here.


    I have also read Kreiger's diatribe on twist rate and another barrel maker as well, can't remember who it was now, but he is very well known. Yes those guys make lots of barrels, but the guys who wrote the article Razor74 is talking about shoot lots of 1000+ yard rounds every year, probably more than Kreiger or the other guy have shot in their lifetime.


    I actually went on an internet study spree trying to find out the FACTS about the prime twist rate for certain calibers. The funny thing is that it seems as if it isn't a completely exact science. Until recently most people had never heard of using a 1:8 twist barrel for a .30 caliber bullet and the people that asked about were usually laughed at. The thing is with a 210-220gr bullet I won't lose any accuracy at short yardage and anything long range the 1:8 will keep the bullet better stabilized through the tran-sonic barrier. Do a little research and you will see all kinds of people having great results from faster twist barrels. The standard twist rates have obviously been around for a long time, but just because they have been doing it that way for a long time doesn't mean it can't be improved upon. My self I would never go higher than 1:10 in a bolt action .308 or 300WM. Why limit yourself to lightweight short bullets offering poor ballsitics. I have buddy who has a high end ($4000+) bolt gun with 1:12 twist and he can't shoot 175gr and up bullets consistently long range. The bullets won't stabilize and he is limited to about 700-800 yards because his twist rate. I tell him that's why but he won't believe me. This is all really just the opinion I have formed by shooting and studying, and I can't claim I am 100% correct. I just like faster twist rates and longer, heavier bullets with high BC.

    Optimal twist rate is dependent on projectile bearing surface. The rifling does not care what weight the bullet is, only how much of it can be engraved. Longer bearing surfaces don't do well in loose twists.

    With a lot of the target bullets, as the weight gets heavier, the bullet bearing surface also increases, but secant ogives and long boat tails cut into this length as well.

    The next issue has already been mentioned, which is gyroscopic stability. Since many of us are interested in long-range performance, we want the projectile to spin faster at distance to maintain stability. There are charts and programs to compute your stability factor with a certain twist rate, bullet type, and barrel length.

    There is a corresponding relationship between spin stability, twist rate, bearing surface, and barrel length, which is why DTA uses a tighter twist on the 16" covert. To get an equivalent bullet to spin well at 800-1200yds from a shorter barrel, you need a tighter twist because you're starting with slower speed.

    A tighter twist then has implications for internal ballistics, because start pressure changes. Now that the twist is tighter, the projectile needs more force to drive it into the lands, generating more peak pressure compared to an equivalent charge with the same bullet in a looser twist.

    There does seem to be merit with the shorter bull barrel and tighter twist, which Todd Hodnett has been getting unusual results with in both .308 16" barrels and .338 LM 20" barrels. If you follow what he's been doing, he has experienced better long-range accuracy with the short, tight twist bull barrels well past 1000yds.

    So I actually do think there might be some merit to the experimentation with a 1/8 twist in the .308 16" with 175's. Todd was pushing to keep the bullet spinning consistently as it passes through the transonic barrier, and his results seem to indicate that he achieved that in spades, especially when a tight twist 20" .338 TRG is grouping better than a 29" at 1 mile. Very few shooters actually have the skill and experience to do any type of conclusive testing at those distances, but as long-range shooting becomes more popular, I think these numbers will grow.

    Well said and worth reading for anyone who thinks 1:10 is the max twist rate for a .30 caliber bullet.