98Z5V

Just the opposite, for distance. Sectional Density ties in with ballistic coefficient, to get those projectiles downrange with accuracy. You're constrained to a fixed diameter, per caliber. Heavier projectiles have to be longer, considering the same projectile construction (with a few exceptions). Lighter projectiles will weight less. Sectional density it a projectiles weight for it's diameter. Ballistic coefficient is the drag on the projectile as it flies through the air - it's shape is the biggest factor. Here's probably the best articles on sectional density and ballistic coefficient: https://www.chuckhawks.com/sd.htm https://www.chuckhawks.com/bc.htm For a short distance, and accuracy testing, the lighter projectiles will get it done - if they don't have a terrible ballistic coefficient. It has to be something decent. .45ACP has the ballistic coefficient of a brick. Not what one would use to determine accuracy at any kind of distance, outside of pistol-range.

One bad thing you're facing on the .308 diameter projectiles - sectional density drives accuracy at range. The lighter .308 projos suck at sectional density numbers. Most "awesome" .308 projectiles that people think of are 168s and 175s - and those SUCK at sectional density. The lightest .308 Win loads that I load are Hornady 178gr HPBT projos, because the BC is higher, but the sectional density starts to climb there... I'm loading 195gr HPBTs now, just due to the BC - but it's really about the sectional density difference. There's a giant difference on the 178s and 195s. At either of those weights, on 300BLK, you're approaching subsonic, and defeating the purpose of accuracy testing. For the 300BLK, go as light as you can, and get the speed up as much as you can, because you're going to be fighting sectional density. If accuracy is the goal. The biggest thing in this fight will be "what distance?" Just due to the huge variance on projo weights. Determine "how far" you want to be accurate, then look at the projectile weight in 300BLK that will get you there. It's a balance, with this cartridge, lighters flying faster, but having shiity sectional density. It's really gonna be a trade off... Sorry to be that guy that pees in the pool... ?

30BLK is low 100s to 220s, man. It does everything. Supersonic to the-most-quiet-subsonic, at 220s. It was designed to battle-back against a 7.62x39 - and do alot more than the 7.62x39 could ever dream of. It excels at that - but you need to pick the projo that will do what you intend to do - accurate - and go with one of the light ones. Very light. Who knows what kind of accuracy you'd get from the 220s - but the range on them was never designed to go 100 yards. That was for max-quiet, at room-distance. This is a tough cartridge, man. Just because of everything it will do, from far extreme to the other far extreme.

My 150 loads are about 1800fps. Not enough to set off Tannerite at 100 yards. Been down that road, with solid hits. Takes 2000fps to blow it. 150s are not what you should load for accuracy testing. They're badass, for General Purpose use, and all I'll load - but they're not for accuracy. They won't help you, and nothing heavier will help you. This is 300BLK, here. Get that projo weight down, WAY down...

His rifle prep was the huge part of the accuracy - to include the prep of the barrel threads with lapping compound, for true barrel mating to the receiver. Those guys were the best "accurate shooters" that there were, with the most handloading knowledge, and the most (unheard of) gunsmithing knowledge, at the time - that's the only way they got "invited to the warehouse" in the first place. And the produced groups in the tens. Repeatedly. Shot after shot. They could even tell you which shot was the "fouler" and would be off by so much, after cleaning the barrel. Shot groups that are 0.010" in difference. That's all in the same hole...

Make sure you do it in a supersonic load - for sure. Something in the 110~125gr loading, or the data might not matter. Here's my $0.02 on that part: I have a solid copper, 911gr projectile, in .510 caliber, that was designed as a subsonic projectile, for the cartridge it was designed for. It was never meant to go supersonic - and I have no idea what kind of casing or charge that you would have to design to make it do that. It was strictly designed as a subsonic cartridge that would have an accurate effective range of 1000 meters, quiet, delivering a payload that will crush an engine block. When we look at the ballistic coefficient of projectiles, you'll see people say "500" or "600" - those are DAMN good BCs! Those are usually G1 BC drag models, and the real number is (for example) a 506 G1 BC for the Hornady 6.5mm 123gr ELD-M projectile - for it's sectional density, that is one badass projectile. But the G1 BC is ZERO POINT 506. It's a .506 BC. This 911gr Projo in .510, if it was ever designed for supersonic, or would GO supersonic, is a 1600 BC. 1.600 ballistic coefficient. The cartridge, and the load, is everything. To get accuracy out of the 300BLK, and determine it's max-best, it will definitely need to be a supersonic load. @Robocop1051, for your 500 Blackout comments, my brother...

I will say this, about barrel length, though... and I was shocked. I built a pistol caliber AR, an AR45, with a 16" barrel. When I went out to finally shoot the thing, I shot it at 25 yards, and it was dead-on. So I shot it at 50 yards - dead on. I had steel at 100, 150 and 200 (and way beyond that). I decided to try it at those steel targets, and I was shocked. It nailed al IPSC steel target at 100, so I went 150, held about the head - hit it. Went to 200, held top of head, and hit that one, too. Went to the 250, and I couldn't figure it out, but it didn't matter... I just hit something at 200 yards with a .45ACP!!! I went back to the 200 yard target, and kept hitting and hitting... It was SO WEIRD to shoot a .45ACP at 200 yards and hit the target everytime. Well, unless you're Larry - he can do that with a 1911... In the throat... I could never do that with a 5" 1911 - but the 16" barrel made the difference. On a round that starts out as subsonic. My point in that is this, and it's simple - it's the cartridge. You need to look at that cartridge that the guys in the Houston Warehouse were shooting, before you try to make a 300BLK perform like that cartridge.

I'm trying to stop you before you spend a bunch of money that you don't need to. I think you're going about this on the wrong set of data points (Houston Warehouse). Barrel length does not affect accuracy, it affects velocity. Here's a great read on that: https://www.wideopenspaces.com/the-truth-about-barrel-length-muzzle-velocity-and-accuracy/ In some circumstances, shorter barrels can be more accurate than longer barrels, and that's specifically due to "barrel whip." I can make a 1/4" wooden dowel that's 2 feet long, flex, just by shaking it up and down. I can't make a 1/4" wooden dowel that's 6" long flex, no matter how hard I shake it. Here's a decent vid on barrel whip - watch the volume, the music gets loud quick: Here's another one, really short: Fact - shorter barrels whip less. Here's the best vid out there on barrel vibrations and harmonics: There's alot more in this, that you'd need to look at, before you just spend money, man. The best way to find out the magic barrel length for 300BLK, inch by inch, is to cut it down inch by inch - and make sure you recrown it every time. You sacrifice ONE longass barrel that way. Once you find that happy number of "the best accuracy,", you get another barrel, and sacrifice that one, going in 1/4" lengths. It's just like loading precision ammo. Don't go down that rabbit hole, thinking you'll make 3 barrels, and one is gonna be the best - you might pick all three lengths that absolutely suck - then you'll think the cartridge sucks, and it'll never be accurate. That's my $0.02...

Indeed. I grew up in Ohio like that - you had two choices for deer hunting. Bow or shotgun. It was slug all the way.

Turn that bipod around, or it's gonna fold on you when you load it up... I'm just sayin'... You push into that thing, and you'll have muzzle device-in-dirt.

Hey, Phantom - you don't need to PM me with nonsense - defend it publicly, or stop talking about it. I don't need to hear about it in PMs.

You real quick tell me how many MOA turret clicks I need to shift 2.5 mil left at 845 yards in order to account for my wind... I can tell you real quick that I need to turn 2.5 mils on my MIL DIAL and I'm good. And you're sitting here doing math to figure it out, which is nonsense. I bet you'll get it, and you post up the answer - I'm not going to figure it out, because I don't have to worry about it. But you will post it - with the luxury of time. Then you'll tell everyone that you just did it off the top of your head, which will be bullshiit. I will tell you that I will observe the bullet strike 2.5 mils left or right, off-target, and I will just SIMPLY dial quickly, and it's done. I don't even have to think about it. I don't even have to do unnecessary math in my head. My follow-up shot is already on the way. If I'm running an MOA scope, and I need to shift 8.59425 MOA left to account for my wind, I'll dial up 8.5 MOA and get it on. That's 2.5 mils, by the way. Fucking nonsense.

It's like having a mile-an-hour speedo in your car, yet you're driving in an area that's nothing but km/h. You're always doing more math in your head, and it never stops. What's the point of going through the extra (completely unnecessary) steps in the first place? It makes ZERO SENSE. Z.E.R.O. You're sitting here trying to pimp this like it's the next best thing - and the reality is, everyone in the long distance world pushed to have that kind of crazy crap eliminated! If one is mil - then make the other one mil, so we don't have to take the EXTRA UNNECESSARY STEPS. If it's MOA, then make the other one MOA... Cool, we like it. You're acting like this is the next best thing now, because you read some shiit from Millett. It's complete nonsense.

This is VERY HONORABLE, and immensely cool, brother.

I cannot even imagine fighting TactiCat, at 8lbs - let alone if the little angry fucker was 40lbs...

Pretty damn good to see you posting. Now, stick with it and come around... You are still owed a trip out here...

Yes, they do. They were behind the .260 Rem push, before SOCOM lost their minds and went 65C.

That almost sound like a 405gr projectile from the 45-70. I have WAY MORE than 250 rounds of Winchester military buck stored up.

You still don't get it.

I didn't think you were talking about this place - I was more commenting that : I'm surprised that garbage is still going around, and people haven't taken the time to research it. They just keep repeating it.

I'm pretty sure that we consistently state here, that you can use either ammo. And specifically stated that it's the older surplus NATO chambered rifles that shouldn't be using .308 Win loads. So, we're consistent in what we say. You just read some garbage somewhere else, I'm guessing...

I have one of the originals on a 16" 5.56 gun - it's a good stock, solid as all hell.

Thanks for the education - you're missing something, though, and it's big. You buy a mount that's got the elevation built into it, if you intend to shoot long distance. LaRue OBRs have that built right into the upper and rail. Solved. I was shooting 17+ mils of drop to 800+ yards on the 25/45. Not a big deal. One thing you don't want to do is mix mils and MOA, like you're suggesting. If I observe an impact downrange that's one mil off, dial that in for me in MOA... Doesn't make any sense...

Aero "acquired" BA a few years ago.

Someone had to make a 308-sized platform to shoot a round that's gonna fit in a 5.56 mag, because they had bolt-face diameter issues and couldn't make it work any other way. That's a compromise on a compromise, right there. I'll take the 500 Blackout...