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All things 300 AAC BLACKOUT
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PostPosted: Thu Nov 03, 2011 9:21 pm 
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The US Military rates the Max Effective Range of the M4 as 500 meters for a point target.

If the max effective range of the M4 with M855 at 2900 fps is 500 meters, that has 100 inches of drop, 41 inches drift, and 291 ft/lbs of energy:

16 inch 300 AAC BLACKOUT 125 grain at 2220 fps has:
100 inches drop at 440 meters
41 inches drift at 484 meters
291 ft/lbs of energy at 700 meters.

The military tends to go by hit probability rather than energy. If we use the drift and drop range as being correlated with hit probability, and discount the energy advantage of 300 BLK, we get 462 meters.

Using M4 military hit-probability standards, the max effective range of 300 AAC Blackout from a 16 inch barrel is 460 meters.

From a 9 inch barrel (2049 fps):
100 inches drop at 410 meters
41 inches drift at 470 meters
291 ft/lbs of energy at 625 meters.

440 meters for a 9 inch.

300 BLK from a 9 inch barrel has the same energy at the muzzle as a 14.5 inch barrel M4, and about 5% more energy at 440 meters.


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PostPosted: Fri Nov 04, 2011 2:08 pm 
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42.

The answer is 42.


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PostPosted: Sun Nov 06, 2011 11:18 am 
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300Blk wrote:
The US Military rates the Max Effective Range of the M4 as 500 meters for a point target.

If the max effective range of the M4 with M855 at 2900 fps is 500 meters, that has 100 inches of drop, 41 inches drift, and 291 ft/lbs of energy:

16 inch 300 AAC BLACKOUT 125 grain at 2220 fps has:
100 inches drop at 440 meters
41 inches drift at 484 meters
291 ft/lbs of energy at 700 meters.

The military tends to go by hit probability rather than energy. If we use the drift and drop range as being correlated with hit probability, and discount the energy advantage of 300 BLK, we get 462 meters.

Using M4 military hit-probability standards, the max effective range of 300 AAC Blackout from a 16 inch barrel is 460 meters.

From a 9 inch barrel (2049 fps):
100 inches drop at 410 meters
41 inches drift at 470 meters
291 ft/lbs of energy at 625 meters.

440 meters for a 9 inch.

300 BLK from a 9 inch barrel has the same energy at the muzzle as a 14.5 inch barrel M4, and about 5% more energy at 440 meters.



Robert,

Agree with your analysis; your comparison agrees with the characteristics of the M4 as shown in the Army M4 Study Guide [http://www.armystudyguide.com/content/army_board_study_guide_topics/m4/m4-study-guide.shtml].

The Army definition of Maximum Effective Range is "The distance from a weapon system at which a 50 percent probability of target hit is expected, or the tracer burnout range." [copied from FM 101-5-1 Operational Terms and Graphics http://www.fas.org/man/dod-101/army/docs/fm101-5-1/f545-m.htm]. So, we can surmise from your study that the 300 BLK could probably meet currently Army ballistic requirements depending on the load and bullet choice since energy at the target is not part of the definition.

May I respectfully add that for hunting whitetail deer with the 300 BLK we should limit shot distances to those that will provide adequate energy to ensure a humane kill - which are going to be much closer in. I don't want to resurrect the arguments over who to believe in this argument, the "1000 ft-lb into the boiler room", the Taylor Knock Out value, etc, and I know that many deer have been killed with .22 rimfire shorts. Heck somewhere there is probably a guy who stabbed one in the eye with an ice pick and killed it.

Here is the Hornady 110 VMax at 2350 fps muzzle velocity:
Image

My personal range limit with this load on a large whitetail is going to be around 100-150 yards - around the 1000 ft-lb point. Longer range hunting for me means bringing out the heavier iron 308/.30-06/etc. I really like this 300 BLK round, and think it will really take off, but my opinion is we should recognize it for what it is and adjust our expectations according to the mission. Thoughts?


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PostPosted: Sun Nov 06, 2011 11:34 am 
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The max range for a deep would be based on bullet function. People are considered responsible hunters if they shoot a deer at 50 or even 100 yards with a 357 Magnum. Even if you disagreed with that, surely you would agree it is fine to shoot a deer a 5 yards with a 357.

300 AAC BLACKOUT has as much energy at 300 yards as a 357 Magnum revolver does at the muzzle. So, if you would shoot a deer with a 357 from up close, then you can shoot one with 300 AAC BLACKOUT at 300 yards - provided the bullet is functioning at that velocity.

The Army study guide used 2970 fps as the muzzle velocity of an M4. I was under the impression it was 2900 fps. Which is it?


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PostPosted: Sun Nov 06, 2011 11:48 am 
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300Blk wrote:
The Army study guide used 2970 fps as the muzzle velocity of an M4. I was under the impression it was 2900 fps. Which is it?


2970: http://www.armystudyguide.com/flashcards/flashcards.php?cat=23&qnum=27

I dont know if that is for a specific round or a max or min Picatinny came up with - I'll check into it...


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PostPosted: Sun Nov 06, 2011 12:34 pm 
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Robert,

Updated info -

Answer to your velocity question: with the adoption of the M855A1, most M4 nomenclature will now show the increased velocity of the new round: 2970 fps.

See: http://w4.pica.army.mil/PicatinnyPublic/news/images/highlights/2011/M855A1/EPR%20Presentation.pdf

2900 is quoted in the original Colt M4 brochure [http://web.archive.org/web/20110616210348/http://www.colt.com/mil/M4_2.asp], which was the correct vel before the adoption of the new round: "...- Accommodates the full range of 5.56mm ammunition, including the NATO M855/SS109 and U.S. M193, utilizing a rifling twist of 1 turn in 7 in. (178mm)...".


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PostPosted: Sun Nov 06, 2011 12:53 pm 
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mechanicus wrote:
300Blk wrote:
May I respectfully add that for hunting whitetail deer with the 300 BLK we should limit shot distances to those that will provide adequate energy to ensure a humane kill


It's not energy, it's the damage the bullet can do that matters. A hunting max range would need a standard for testing. First determine a minimum penetration requirement for the size of game. Max hunting range would be where the bullet still upset and met the penetration minimum.

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PostPosted: Sun Nov 06, 2011 7:45 pm 
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-k- wrote:
It's not energy, it's the damage the bullet can do that matters. A hunting max range would need a standard for testing. First determine a minimum penetration requirement for the size of game. Max hunting range would be where the bullet still upset and met the penetration minimum.


I concur its not just the energy. Never would I advocate looking solely at energy ignoring bullet design - I'm sorry if that came across in my posts. A Tungsten flechette dart and a pure lead wadcutter slug, both weighing the same and flying at the same velocity, would have drastically different terminal effects on a deer.


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PostPosted: Mon Nov 07, 2011 1:41 pm 
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There's always one per thread at the least. A firearm is a tool and must be used accordingly, thank you for the comparison.

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PostPosted: Mon Nov 07, 2011 1:47 pm 
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On another note I get so tired of people saying what "x" can't do, I think you should pic your tool properly before you start your work. I don't think Robert is selling us a 800 yard hunting rifle. Lastly what is the average distances for ethical harvesting of game "deer" mean, median and mode? I'm sure you may be surprised.

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