Questions About .300 Blackout Ammo

[.308 Norma]

Our middle grandson (home on leave from the Army), Matt showed up out at the house this afternoon with a like-new AR-15 chambered in .300 Blackout. About all I know about the cartridge is that I’ve seen it mentioned on THR quite a few times. I am interested though and will probably learn more about it seeing as how Matt got himself one.
At any rate, Matt had a couple of boxes of ammo for it (that his buddy sold with the rifle), and they were all loaded with 200gr bullets. Is that normal for .300 Blackout ammo? They were nice looking rounds, but those big ol’ 200gr SP bullets looked kind of long for those little cases, and it said on the boxes that they were subsonic - for suppressor use, I guess. Is that right?
Thanks!

 

[mavracer]

Yes the 300 typically has 2 loadings the 110to 135ish supersonic loads and the 200-220 subsonic. There are some 147-150 FMJ loads also and really if you reload you can stick about anything .308 in it.
It's really a fun cartridge to shoot and easy to load for.

 

[hso]

Subsonic loads aren't automatically fore suppressor (although you get significant benefit in sound reduction using a suppressor with subsonic ammunition). My subsonics are 200 and 220s.

It isn't uncommon to see typical .308 bullets loaded for .300 Blackout. I have several boxes 147 and 175 gr .300BO.

You'll find commercial ammunition loaded 110-150.

 

[LoonWulf]

I used to run 245mbcs at about 800-850fps with w231...... no suppressors out here but that loads pretty bloody quiet without.

i feel like the supersonic 300whisper/blackout is basically what the 30carbine tried to be, and would use it for the same kinda things

 

[wesmonster]

Yup, most subs are 200 grains or better.
Most commercial loads are the long bullets, been told that's to keep it from chambering in a 5.56 barrel. Assuming there's no bullet setback.
I do have some 220 gr. commercial reloads with 'stubby' bullets but all the Sig Sauer, Hornady, Mag Tec and S&B use the 'long' bullets, from 147 to 200.
Good caliber, shoot it in ARs, Ruger bolt action and a Mini-14.

 

[mavracer]

I used to run 245mbcs at about 800-850fps with w231...... no suppressors out here but that loads pretty bloody quite without.

In my 16" Ruger American I use Unique with 208 A-Max and 200 Maker Rec and yep they're pretty quiet without the can about like 22 standard velocity from a rifle, of course like the 22 with a can they're Hollywood quiet.

 

[.308 Norma]

of course like the 22 with a can they're Hollywood quiet.

 

[horsey300]

Lehigh and Hornady (I think) made sub expanding ammo/components, the Hornady is a 190 I think, on paper they trip my trigger so to speak, and the 125ish sonic loads should be just plain fun, tbh I'm looking forward to a 10.5" 300bo sbr with a can, but that's paperwork down the road.

 

[Phaedrus/69]

I like the 110-115gr stuff myself. It's cool that the .300 Black has such a wide range of bullets from 90gr frangible rounds up to 220gr subs. To keep velocity where I want it I try to run 125gr and below, pretty decent velocity to get that rifle-type terminal effect and decent trajectory while offering a bit more bullet mass vs a 77gr from the 5.56. Plus, subs aren't that appealing to me as I don't have a can.

 

[Casefull]

If you like mortar type trajectories, the heavy bullets do that well. Lol

 

[FL-NC]

On my 300 BLK, if I zero with subs at 50 yards, they drop about 7" when it is at 100 yards. Hornady told me not to expect the sub-x to expand past 100 yards. Definitely suitable for short range use, and that's about it.

 

[eastbank]

i run a rem md 7 aac bolt with a threaded 16" barrel(no can) with 125gr-150gr bullets with lit-gun, its a nice light short carrying woods rifle with in its capabilities and that 125-150 yards for me. i have killed several deer with it and with double broadside lung hits they go down. the loads i use are not for semiauto rifles, i laddered up my loads and they are safe in my rifle. both the 125 and the 150 gr bullets sighted in at 200 yards carry 1000 fpe and 1800+ fps at 200 yards and only about 3" high at 100 yards.

 

[Gordon]

Really got into .300 BO in ARs and bolts last decade from .300 Whisper in a suppressed T/C Contender in 90s . To get sub sonics in 8-10" barrels to function pistol length gas is your friend. Running subsonics in a 16" barrel pistol length gas makes 100% function much easier . Super sonics like carbine length gas in 16" barrels . The 125 grain supers from 16" barrels at 2200+ fps seem to be pretty identical to 30-30 in performance on deer. The 110 grain fast openers at 2300fps should be deadly defense rounds to at least 200 yards . Drop the barrel to 8-10" with supers you can get 2200 fps with the 110s and 2100 with 125s and they still expand to 150 yards at least. . The .300BO is a great round to reload and ammo from the big reloaders is really getting cheap. I see 110 hps or 150FMJ 200 round boxes for $125 lately. The .300 BO is right there with 7.62x39 AK ammo in performance , and just a smidgeon less than 30-30 with it;s 150 grain bullets at an actual 2200 fps from a 20" barrel and the .300 BO 150s at 1950fps from an 18" barrel from factory loads. The reloading advantage is much less powder used for the .300 BO for any given load range = less sound output overall.