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Posted: 8/11/2015 11:53:18 PM EDT
| I already have a SBR in .300 BLK. From doing all the research, I have concluded that this ammo is designed for CQB work. I want to build another AR for long range work using a .30 caliber projectile or anything larger than .223/5.56. Since the .300 BLK is made for convenience, could this caliber used for long distance shooting? Say a 16" barrel? I am looking for improving ballistics, accuracy, and performance for longer ranges over the .223/5.56 ammo. |
| All my 300's are SBRs and I have never shot them passed 200 yds but I never really thought of 300 blackout as a long range projectile. I've heard some guys love the 300 BO as a long range caliber but from my understanding is that it was never designed for it. I thought if I were to go long range I would just go with 7.62 x 51 ar10 and I could reload the same 308 bullets but with more of a punch |
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.300 blackout, and .338 spectre have a real potential at longer, than anticipated, range if you are extremely proficient.
At subsonic speed, the only energy lost is that shed to the air through which it travelled. So bullets which have an high mass to caliber ratio and excellent ballistic coefficients retain MOST of thier energy for the whole duration of flight. Restated, at six hundred yards these big slow bullets can retain 90% of thier rather limited muzzle energy. These bullets do not shed energy into a "sonic boom." The bullet does not waste energy generating noise. In effect, the bullet is passing through the air slow enough to let the air easily move out of the way. NO shock waves are generated. Thus at six hundred yards a .300 blackout can hit almost as hard as a .45 acp at the muzzle. So why is it not a long distance caliber? It takes almost two seconds to travel that distance. In the first second the bullet will drop thirty two feet. By the end of the second it will have dropped one hundred twenty eight feet. Restated, that is 128 FEET or 1,536 INcHES. What is the height of view of one'e scope? What can the mount account for? What is the exact range. All this is needed to overcome the horrible angle of attack. Two seconds exposure to wind will not make this easier. With practice this can be done. Some of the recorded black powder shots are not recognized as awe inspiring achievements, until practice includes something like this. DB Edited to add, this is beyound my ability. But, I am imagining the damage caused to a deer, by a head on shot between the eyes travelling throught the head, neck and entering but not exiting the thorax. |
| I figured that other calibers are better choices but really looking to see if the .300 BLK can be a contender because of its convenience. I am trying to avoid using proprietary parts for other calibers since I already have a good supply of AR parts, magazines, and .223 brass. My intentions are not for hunting, but mainly target shooting out to longer distances, not limited to exceeding ranges with the .223 cartridge. I won't be shooting subsonic loads until I get a suppressor for it. Is it possible to setup a .300 BLK precision rifle? |
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When I lived in Northern WI and I shot on my uncles' land .300 blackout would have been sufficient. Two hundred yards would have been a LONG shot. Within that range, 110-130 gr. Blackout supersonic is enough, if only just, for white tail deer. For me, then, it would have been excellent. So how will you use your rifle? What kind of distance will you be able to cover. How much retained energy will be needed for your target? If you can answer these questions the forum will be better able to steer you in the right direction.
How much experience do you have with a carbine chambered in thirty-thirty? Because it is comparible to, but better than, the blackout. DB |
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Now that I live in Southern WI it is easier to practice at ranges greater than which I can hunt. So I can finally JUSTIFY the .308s I have used all this time. As the old arguement that they fire cheap ammo no longer applies.
These days a cz 527 bolt action chambered in .300BO looks very tempting, to me. DB |
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what do you consider long range ? 300 yds , 500 yds , maybe 1000 yds ? I understand what your wanting to do but sometimes it just dont work out . I think the blackout is a great cartridge and own 3 of them an 8.5 inch pistol , 16 inch carbine and a remington bolt action they all serve their purpose but if I was wanting to shoot paper with a super-sonic round at 1000 yds I would look elsewhere . I can give you my dope for a barnes 110 grain zeroed at 100 yds traveling 2415 fps over my chrony out to 500 yds . I have no info for any farther since I have no place to shoot any farther than that .
200 yds up 3 moa . 250 yds up 5 moa 300 yds up 7 moa 350 yds up 9.5 moa 400 yds up 12.5 moa 450 yds up 15.1 moa 500 yds up 18.4 moa at 500 yds that is right at 96 inches of drop . this is the info for my bolt gun I dont shoot the other 2 much over 100 yds . 
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| I consider long range as the maximum effective range of the 5.56 cartridge, which is 600 meters. Will the blackout reach that far while improving ballistics? If it requires skill, special barrels, and adverse conditions then I'll have to get an AR in a .308. I was hoping to create a precision AR in a different caliber with having extra usable parts around. I want something that is accurate up to that distance. I already have a SPR in 5.56 but would like to build another one that can hit harder within the same ranges. |
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According to Shooterscalculator, using the data from my 300BLK 110gr. Barnes reloads (2410 fps at the muzzle from a 16' barrel, zeroed at 33 yds. with a sight height of 2.375 inches), the round would be traveling at 1102 fps with 297 ft. lbs. of energy at 600 yards. You could punch holes in paper but the drop is 150 inches. |
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Quoted:
I consider long range as the maximum effective range of the 5.56 cartridge, which is 600 meters. Will the blackout reach that far while improving ballistics? If it requires skill, special barrels, and adverse conditions then I'll have to get an AR in a .308. I was hoping to create a precision AR in a different caliber with having extra usable parts around. I want something that is accurate up to that distance. I already have a SPR in 5.56 but would like to build another one that can hit harder within the same ranges. skill is required in any type of shooting if you mean improving ballistics by a flatter trajectory then you will be dissapointed with the 308 as well . a free lunch does not exist when it comes to ballistics . |
| I recently sold my 300 BLK 16 inch upper, to fund another project, but I found it to be very accurate out to 300 yards. I think the 300 BLK is very capable out to that distance and a pleasure to shoot. I loaded 125 SST with IMR 4227, and according to Strelox the round was hitting with 513 ft pounds of energy at 300 yards. I liked the setup because at that distance it was a 3 mil hold over, about 1 mil at 200 and zero at 100 yards. There are other caliber choices that are more capable at 300 yards and beyond but, the 300 BLK is far from a toy. I like the 300 blk and it is a good choice for medium game, self defense and target shooting out to at least 300 yards. My 300 BLK is now limited to a 8 inch barrel and it shoots well out to 300 yards, with less energy. As kind of a side note I decided to go with a 300 BLK over a semi auto .308 because of weight and cost, and I plan on building another 300 BLK with a 16 inch barrel in the near future. |
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There is a boatload of different chamber offerings these days, from 6mmx45, 25sharps, 277WLV all based on the 223/556 brass, with the 25sharps and 277WLV having commercial ammo being available. Then there are just as many offerings based off the 6.8 brass(though none are commercially available atm). And then there are the more exotic offerings based on x39/Grendel brass and even 6.5x47Lapua based wildcats.
If you want a real distance shooter with the AR platform look into the 7mm VAR. |
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Quoted:
There is a boatload of different chamber offerings these days, from 6mmx45, 25sharps, 277WLV all based on the 223/556 brass, with the 25sharps and 277WLV having commercial ammo being available. Then there are just as many offerings based off the 6.8 brass(though none are commercially available atm). And then there are the more exotic offerings based on x39/Grendel brass and even 6.5x47Lapua based wildcats. If you want a real distance shooter with the AR platform look into the 7mm VAR. Tactical Ammunitions has 6x6.8 ammo 
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| For my 2 AR10's in 308, one 10.5 inch barrel and the other is a 16 inch barrel. 44.6 inch adjustment for 500 yards on the 16 inch barrel vs 111.3 inch adjustment for the 10.5 inch barrel. I don't expect to use my shorty beyond 300 yards. Wasn't meant for a long range weapon. As was posted above, what range are you considering "long range"? Just thought I would add my info for your research since 308 was mentioned. Hope it helps. |
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