Is the Love Affair Over? (300BO)

762x51

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if money weren't an issue and we werent experiencing the ammo shortages that have for the last year, my cartridge of choice for the 15 would be the 6.5G. never got on board with the 300BO as i had several 308's and a creedmoor.
 

azsugarbear

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The 300 Whisper (grandfather of the 300 BO) was designed on the back of a napkin over dinner by JD and some special force guys. They had been complaining that the 9mm subsonic was just not enough. It was taking multiple shots to put a bad guy down quickly. JD came up with a cartridge that was based off the 221 Fireball (same base dimensions as the 5.56 Nato) that became known as the 300 Whisper. When AAC wanted to SAAMI spec the 300 Whisper and produce it for the mass market, JD was not interested. So they changed the design by a few thousandths of an inch here and there to sidestep patent issues - and the 300 BO was born.

Make no mistake, the 300 BO/Whisper was and always has been mission-specific: sub-sonic lethality at relatively close range. To make it a commercial success, AAC and the ammo makers had to broaden its appeal. It was never intended or designed to be a "do all" caliber. It does one thing extremely well. And it can do a couple of other things OK - as long as you understand ballistics. Many guys tried to load the 300 BO with heavy rifle bullets (230 gr. Sierras come to mind) expecting great results. The fact that these bullets needed at least 1,800 fps minimum velocity to expand never entered the equation. They thought that a tumbling bullet would be just as effective. What they got were inconsistent kills.

If you want great killing power with sub-sonic performance, you need to load 30 cal. bullets designed to open a pistol velocities. Lehigh defense makes great bullets and ammo that accomplish this purpose. Several other companies make just the bullets like Outlaw State. The other end of the spectrum is to shoot super-sonic rifle bullets with enough velocity to reliably open at the distances they hope to shoot at. Because of the small case, this necessitates lighter 30 cal. bullets to reach those velocities. This creates another problem: light bullets bleed off energy/velocity rather quickly. You need a chronograph and then a ballistics program to understand where your velocity drops below the minimum velocity required to open reliably. Most guys didn't do this. They thought they had a 30-30 round in an AR platform. This was not the case. The 300 BO can take deer and pigs reliably using varmint style bullets that open quickly out to a range of 100-150 yds, but again - that was not its original mission.
 

rustyshackleford

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I’m pretty certain subs and supers were the original goal. I can’t imagine preferring a 220 gr bullet with less frontal area over a 230 with more at the same speed. 220’s at 1050 to be discreet and 110’s at 2000-2200 to reach out to ~200 I can understand. For guys in those circles it makes a lot of since to replace an MP5 with a harder hitting gun with AR ergos that is quieter and then once it gets loud change mags and now you are also hitting harder than a Mk18. Seems straight forward to me. I just built one and am getting 2025 ft/sec from a 7.75 barrel with a 125 SMK and I’m nearly a grain under max.

For hunting I don’t think it’s ideal. At least not anywhere past 100 yards or so. 6mm arc or 6.8 SPC would be my preference for a deer cartridge in an AR personally.
 

MZmoose

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I know there is probably still a hard core group that's still in love with the 300BO but it seems that the love affair is over and you don't hear about it as much anymore. I was and still am a fan of it's grand daddy the 300 Whisper as originally introduced by JD Jones waaaaaay back in the dark ages for the Thompson Center Contender but never got one in an AR nor did I consider it a serious medium to big game cartridge.

My new love affair is with the 6.5 Grendel for everything from 1000yd targets to prairie dogs to hogs and whitetail and I've heard it suppresses very well but I haven't gone that route yet.

What do y'all think? Has the Grendel eclipsed the Blackout?

It seems to have so many more capabilities and it seems to be so much more versatile.

I hope this doesn't start a ****ing match but rather a good discussion of the good, the bad and the ugly of each cartridge.
I've hunted with the BO and feel it's ok supersonic and have had bad luck with subsonic loads on pigs. The Grendel is a superior hunting round and will definitely out pace the BO at the target range. The new 6mm ARC sounds interesting and is supposedly better at long range over the Grendel.
 

azsugarbear

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The original idea sprang from the need to replace a dedicated weapon (H&K MP5) shooting subsonic 147 gr. 9mm bullets in CQB situations. The history that I read, said nothing about super-sonic rounds as part of the original goal. Was it an added benefit? Perhaps. But carrying two different loads into CQB can lead to confusion and potentially a huge mistake if you accidentally load a supersonic round into a subsonic situation. Additionally, the supersonic round would most definitely change your POI, necessitating a recalibration of your sight. I suspect that would not be something you want to contend with in the middle of a firefight.
 

azsugarbear

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JD Jones, an ardent handgunner, has had a long affair with big, wildcat pistol cartridges. He eventually gravitated to modifying rifle cases because of larger case capacity, plus the added benefit of of downrange performance due to rifle bullet BC's. He has tinkered with more rounds than probably most on this planet. His goal was as much supersonic as subsonic. He used his creations primarily for hunting and understood the limitations of each caliber. The 300 Whisper/BO initially catered to the military and was only later marketed to the public.
 

rustyshackleford

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The original idea sprang from the need to replace a dedicated weapon (H&K MP5) shooting subsonic 147 gr. 9mm bullets in CQB situations. The history that I read, said nothing about super-sonic rounds as part of the original goal. Was it an added benefit? Perhaps. But carrying two different loads into CQB can lead to confusion and potentially a huge mistake if you accidentally load a supersonic round into a subsonic situation. Additionally, the supersonic round would most definitely change your POI, necessitating a recalibration of your sight. I suspect that would not be something you want to contend with in the middle of a firefight.
I’ve never seen the original design intent per se but to me it’s not got nearly as much merit without the supersonic component. As far as zero I just zero my supers at 150 and subs are pretty much zero’d at 50. I don’t know how it’s actually used I just know what makes sense to me
 

schmi015

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The original idea sprang from the need to replace a dedicated weapon (H&K MP5) shooting subsonic 147 gr. 9mm bullets in CQB situations. The history that I read, said nothing about super-sonic rounds as part of the original goal. Was it an added benefit? Perhaps. But carrying two different loads into CQB can lead to confusion and potentially a huge mistake if you accidentally load a supersonic round into a subsonic situation. Additionally, the supersonic round would most definitely change your POI, necessitating a recalibration of your sight. I suspect that would not be something you want to contend with in the middle of a firefight.
They have eotech's and Acog's for 300 BLK. They're designed so that you can run both subs and supers without having to recalibrate anything. The whole point is to run subs to remain covert, carry 3 mags or so and if the other people start shooting you can switch to supers 4-5 mags.
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azsugarbear

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I get what you are saying. JD Jones felt the same way. But the military looks at things differently. If it is true that there little merit for a subsonic military weapon w/o a supersonic component, then the H&K MP5 did/does not have much merit either. There is no supersonic component with rifle-like ballistics to the 9mm. And yet the MP5 is still preferred to most other weapons for CQB.

The ACOGS with dual points of aim for the 300 BO came much, much later, well after the initial design of the 300 Whisper. My comments have been centered around the initial design and mission of the 300 Whisper - not what it has morphed into over time as the 300 BO.
 

rustyshackleford

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I get what you are saying. JD Jones felt the same way. But the military looks at things differently. If it is true that there little merit for a subsonic military weapon w/o a supersonic component, then the H&K MP5 did/does not have much merit either. There is no supersonic component with rifle-like ballistics to the 9mm. And yet the MP5 is still preferred to most other weapons for CQB.

The ACOGS with dual points of aim for the 300 BO came much, much later, well after the initial design of the 300 Whisper. My comments have been centered around the initial design and mission of the 300 Whisper - not what it has morphed into over time as the 300 BO.
I didn’t say the MP5 had little merit but comparing an MP5 to a subsonic only 300 blk M4 platform your only real advantage would be ergonomics and modularity. With the advent of IR devices being mounted to handguards it’s probably a bigger deal than what I think but to me the big sell would be killing off two weapons for one. Again if I were looking at it that’s what I would want it to do. I can’t imagine a smaller diameter bullet being more desirable in a subsonic application so if that was the only feature I’d stay with MP5. They are a dream to shoot. So is subsonic 300 blk though
 
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freddiej

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I have both the 300 B/O and the 6.5 Gren. I am disappointed in the 6.5 Gren. I should have ordered the 6MM ARC barrel. I think it's better and has more uses. the 300 B/O is a great in house/close quarters cartridge and it is accurate from 0 to 250 yards. I am not sure why the 6.5 gren does so well in the other places but here it's the second or third most used coyote and dog round here. the only ones more popular are the 223/5.56 and the 221 fireball.
I like the 300 blackout, I should have held out for the 6mm ARC
 

ndking1126

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I had a 300BO and got tired of it very quickly. Before I bought it someone told me unless you are going to suppress subsonic ammo, you might as well get a 5.56. They were right.

I had a Grendel upper for a little while and I really liked it overall. It's the best cartridge for the AR platform IMO unless you just want cheap plinking with 5.56. My issue with it however is that the AR platform is heavy with a 20" barrel and with a 16" barrel the 6.5G is fairly handicapped. It'll still kill hogs, deer, and such, but if I'm going to hunt deer I'll just take my bolt rifle since its lighter and more accurate. If shooting for precision, I'll take my precision rifle that is definitely more accurate and has better ballistics. Hunting hogs is legitimately the only use I can think of that it makes the most sense for. Every other scenario theres a solution that is better suited to do it, and unfortunately for me I dont have anywhere to hunt hogs.
 
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azsugarbear

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I didn’t say the MP5 had little merit but comparing an MP5 to a subsonic only 300 blk M4 platform your only real advantage would be ergonomics and modularity. With the advent of IR devices being mounted to handguards it’s probably a bigger deal than what I think but to me the big sell would be killing off two weapons for one. Again if I were looking at it that’s what I would want it to do. I can’t imagine a smaller diameter bullet being more desirable in a subsonic application so if that was the only feature I’d stay with MP5. They are a dream to shoot. So is subsonic 300 blk though
Remember: we are talking early 1990's - the birth of the 300 Whisper. Some special forces guys were complaining to JD over dinner about having to "double tap" bad guys with their MP5's in order to put them down decisively. JD's answer was the 300 Whisper on an AR platform. One subsonic replacing another subsonic. Any supersonic capabilities of the 300 Whisper was just icing on the cake - but not its primary mission. Although the diameter of the 30 cal. bullet (.308) is smaller than the 9mm bullet (.355), its increased weight allows it to deliver more punch:

147 gr. @ 1,050 fps = 360 ft/lbs of energy at the muzzle
230 gr. @ 1,050 fps = 563 ft/lbs of energy at the muzzle

That is a substantial increase. leaves the 9mm in the dust.
 

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