300 blackout 10 inch vs 16 inch

I agree with shooterrex about the 6.5 Grendel, it’s an all around awesome round. you can also buy cheap steel cased ammo for it. the 300 is a fun round, but the 6.5 has a lot more long range punch. I buy reloads from ventura ammo on 300 and never had a failure.

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If you have the reloading equipment, and a supply of .308 projectiles on hand, it’s not that expensive.

You can take a pile of 5.56mm AR-15 parts, add a .300 BO barrel, and assemble a .300 BO AR-15. The brass can be made by trimming down and necking used 5.56mm brass. And .308 projectiles are generally easy to find and available in a wide variety of weights, types, and prices.

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Even though Bill Alexander will deny it, it 6.5G reliability issues with broken bolts. Some manufactures will comment about things they try. A 6.5mm bullet has a great BC, no doubt.

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And that’s why they changed the chamber and bolt face to the Grendel type 2.

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:+1:

The Whisper/Blackout intrigues me. But I can’t get past getting a sub gun or SBR in .45 auto.

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Find charts for the downrange velocities on 220gr .300 BO and 230gr .45acp (almost the same weight), then compare the two to find at what range the .300 BO projectile will drop to the velocity of the .45acp’s projectile at 50 yards.

That was what got me interested.

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Down range velocity, depending on distance, isn’t really a concern of mine. How far are you thinking? At distance my M4 in the correct caliber gets it done.

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Down range velocity, when comparing projectiles of the same (or nearly the same) weight, determines how well the round retains energy at longer distances. It is also a factor in bullet drop, since bullet drop over time is the same, but will vary over distance as a function of velocity. Two very important factors in determining ‘effective range’.

Been years since I looked at the numbers, but if my memory isn’t off:

  • 230 gr .45acp velocity at 50 yards is the same as 220gr .300 BO velocity at some point past 200 yards.

  • Bullet drop on 220gr .300 BO doesn’t get to the point you have to worry about it, on a torso sized target, until some point past 250 yards.

A braced AR pistol with a 10.5" upper is fairly compact and easier to carry around than a carbine or rifle, and subsonic loads in .300 BO don’t really get enough of a benefit from longer barrels, to bother with carrying anything larger than that. Supersonic loads are another matter, but do offer the option of longer range capability by switching a magazine, if a person wanted that option and was willing to work out the differences in zero and deal with carrying two types of ammo.

Is it a substitute for a handgun? No, it’s bulkier and heavier, but it has much more range.

Is it a substitute for a scoped .308Win rifle? No, it doesn’t have that kind of range and doesn’t hit as hard, but it is smaller, quieter (both suppressed and unsuppressed), and doesn’t beat on your shoulder as much (which is something to think about when considering follow up shots, if they are needed).

It’s also interesting, if you want to play around with what happens when your long range shots don’t have to deal with the issue of the bullet dropping from supersonic to subsonic - I built an AR in .22LR just for this, and got it working reliably just as Sandy Hook happened and .22 ammo dried up (the particular load I was tailoring it for, was still hard to find, last month).

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My handgun or an SBR if I thought I needed it would be for inside 50 meters. Just so you know, I didn’t ask about bullet drop. But I appreciate the discussion. There is always someone reading who might not know.

I have an M4 zeroed for 50 meters which has POI at 200. That is what I meant about not needing distance.

And I don’t have a .45 subgun. It seems like H&K still has the UMP in .45. And I agree the AR platform makes far more sense than the UMP for most people.

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I guess I am inclined to use a 10 inch SBR with 300, and not the 16.

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Ten inch barrel is the route I go. Good for being compact for house/ vehicles. And a ten inch barrel with a 110 grain projectile will have approximately 1153 ft-lbs of energy.
To put this in prospective the same amount of energy out of a 55 grain 5.56 the barrel length would have to be 16”.
Food for thought.

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P.S. I practice what I preach too.

I will put up better pictures later.

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Now that looks nice. What is the accuracy out to 100 yards with supers and subs?

Best article I have read yet!

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Really nice, is at one of em err high capacity clips?

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Yes sir 60 pills.:grin:

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@Sliverback theoretically with a ten inch with supers the velocity should be 2100 FPS. To my knowledge that is more than enough to stabilize a .308 projectile property.
To be honest I haven’t had a chance to shoot this one and only finished it a week ago.
Accuracy at this length will depend on barrel geometry “good machining”.
I will certainly let you know after a range trip.

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Here is an example of the added ME. 9.30
Still impressive

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That’s interesting. The gentleman stated that the 16” has a bigger wound channel, but it almost looks like the 10.5” barrel wound channel looks bigger!?!
What does everyone think?

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I would like to see this done with standard 308 bullets not just the solid copper stuff . Yes he shot SST’s but they just kept on going.

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