AR 15 pistol 300 BO no good

Nuclear Worker

Well-Known Member
LRH Team Member
Mar 26, 2018
Fort Atkinson
On a side note I shot my last one with the hornady sub x ammo. I’ve had no luck with any subs before they just pencil through and either don’t expand or barely expand.
These sub x actually work I shot behind shoulder and had a very nice 1.5” exit wound and lungs were in rough shape. Very nice blood trail on that one.
Might be worth a try for your limited distance shooting.
Thanks for the info


Well-Known Member
Sep 19, 2012
Spring Lake Michigan
I have an 8.5” and a 16” I use the most of. I get very little diffrence in speed from one to the other. I can’t recall what my fps was with the 8.5” but I know is was very close to the 16”. That’s the beauty of the blk barrel length doesn’t play as much of a factor as with the .223.


Well-Known Member
Jan 3, 2017
I'm not knocking the 300 Black out because I don't have one. So I was interested in finding out more about this very popular cartridge.

In my research I found that about the best it could do with a 150 grain bullet was just barely over 2,000 ft/sec in a 16 " barrel. in a pistol velocity would be down from that 2 to 400 ft/sec. Add distance (50 yards) and the 150 grain bullet would be at or below the minimum design velocity of 1800 ft/sec for performance, and you could not expect it to perform perfectly every time, or even most of the time.

I also ran the 125s and found that the best velocity you could expect was around 2400 at best. the subsonic velocity was just over 1000 ft/sec for the 125 and 871 for the 150.

So it looks like the bullet does not have much of a chance to perform at these velocities. Full penetration is easy as long as the bullet does not fragment and damage could be compared to an arrow with a lot
less velocity and energy. In fact many times when I was bow hunting a field tip was used for hogs when they were not good to eat and the desire was for them to run off and not mess your deer hunt. (The arrow normally made a complete pass through). but the hog still died.

Again, not knocking the 300 black out but in my opinion you are asking to much of the cartridge and the bullet when hunting larger game like deer and hogs.

Just my opinion


Hey J E, what were you using for powder on those 150gr loads? I'm running the 150gr Speer gd BLK at 1850fps out of my 7.5" pistol with CFE BLK. They're pretty awesome.
Edit: These were ballistics gel tests done not by myself.

To the op, 300BLK is a great round in certain areas. Same as a 22lr and a 300wm. Sounds like the deer season xp worked well, just didn't have enough oomph to make it all the way through. Since you don't reload it limits your options for a hunting bullet. The 6.5 Grendel will definitely have more options. It also works great in shorter barrels. A 12.5" 6.5 Grendel won't lose much to a 16".
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Well-Known Member
Jun 21, 2017
"The 6.5 Grendel will definitely have more options. It also works great in shorter barrels. A 12.5" 6.5 Grendel won't lose much to a 16"."

IMO the Grendel is not the same type of cartridge as a not the same class.

I don't believe the Grendel was intended to be used as a slow sub velocity loading. For a start the 6.5 bullet selection is no where close to that of the 30 cal.

The smaller bullets allow a lot more room for powder in the case. I see guys complain quite a bit on the Grendel site because they don't get it. They use a short barrel and don't get the velocity they want.

My 20" barrel get a solid 100 fps over my 18" with the exact same load combos. I've tried to tell them 2500fps is a lot better than 2000fps with 120gr bullets.

But they see the BO guys successfully shooting 200gr bullets out of a 8" barrel and think they can do the same thing with 120gr bullets...that's two different animals.