Suppressors 300 BLK Subsonic at 300 Yards?

[MMH]

What would it be like to shoot subsonic 300 blackout at 300 yards? Shooting a 225 gr. match bullet gives you a great BC. Nonetheless, the bullet drop will be almost 100"& time of flight 0.9 seconds. At the same time, shooting at my 308 at 600 yards (178 gr. leaving the barrel at 2550 FPS) results in a similar bullet drop & time of flight.

So, just for some plinking fun, is 300 yards subsonic possible? It would be a riot to be hollywood quiet while knocking over some beer cans.

 

[redneckbmxer24]

We shoot 22’s subsonic with a terrible BC much further than that. 300BLK with a high BC bullet will run a lot better.

 

[Badfinger]

Probably on par or slightly better than with a 200gr 45 ACP round.

 

[Mordamer]

https://youtu.be/dZcvL-M5w80

This is me shooting at 600 yards with subs. You have to listen really close but I think there are 6 hits on the 24 inch plate. This was using a 3x optic.

 

[ohnomrbillk]

Subsonic bullets are an interesting animal.

The BC calculations that are published are based on a velocity much higher then subsonic.

You’d be wise to try several bullet shapes in the 200+ grain weights to see what works best.

Some find the increased bullet weight and a boat tail have a greater effect on long range subsonic trajectory and accuracy. YMMV

 

[deersniper]

The Leupold 300 BLK scope/reticle makes hold overs easier

 

[mdmp5]

At subsonic velocities, projectiles don’t slow down at the same logarithmic acceleration of supersonic projectiles. So BC isn’t as much of a factor. The thing that will make the biggest difference in terms of precision is the repeatability of your velocities

 

[NighthawkCG]

Its possible. Done it plenty. The challenge (like mijp5 said) is getting a sub round consistent enough to always do it. The guys at 300blktalk had a challenge a year or so ago at 200 with subs and could pretty much keep them on a 3x5. Its pretty fun to do. Only done it with 208 A Max handholds.

 

[Seandradamus]

I run a lot of 300 blk , I put a bolt rifle together as a prs trainer for barricades and such out to 400.
Nice and quiet for my neighbors, still provides a bit of recoil just like a 6 mil match rifle.
I bought 1000 ...190cc from shooters pro shop for cheap and load em in front of Bullseye or unique, 2nd choice is 4227 or AA#9.
The trick to low SDs is to load the round short enough to take up the empty space in your case using a bullet that doesn't mind some jump.
My sds are single digit sometimes low teens.
Gun shoots 3/4 Moa always and has produced some .25 Moa groups at 100 yard.
Smacking a kyl rack from 6" to 2" at 230 yards is routine.
10" gong at 400 is easy too. At 5 grains of powder you get a lot of practice for a pound of powder.

 

[Hoser]

Using N-110, Lapua brass and Berger 230s I found a good load that will hold MOA at 300 yards.

Took lots of load development.

 

[mdmp5]

I run a lot of 300 blk , I put a bolt rifle together as a prs trainer for barricades and such out to 400.
Nice and quiet for my neighbors, still provides a bit of recoil just like a 6 mil match rifle.
I bought 1000 ...190cc from shooters pro shop for cheap and load em in front of Bullseye or unique, 2nd choice is 4227 or AA#9.
The trick to low SDs is to load the round short enough to take up the empty space in your case using a bullet that doesn't mind some jump.
My sds are single digit sometimes low teens.
Gun shoots 3/4 Moa always and has produced some .25 Moa groups at 100 yard.
Smacking a kyl rack from 6" to 2" at 230 yards is routine.
10" gong at 400 is easy too. At 5 grains of powder you get a lot of practice for a pound of powder.

What’s your load with 5 grains, and how fast is it? Reason I ask is I just started, and I’ve been using about 10 gr of cfe blk with 220s and I’m just subsonic from what I can tell (they were cracking at around 12 gr)

 

[spife7980]

What’s your load with 5 grains, and how fast is it? Reason I ask is I just started, and I’ve been using about 10 gr of cfe blk with 220s and I’m just subsonic from what I can tell (they were cracking at around 12 gr)

10 gr over a 220 RN should be at the low 900 fps area I think based on my testing so, yes, they will be very quite but still a good ways from cracking. My load is 12.1 gr cfeblk in federal brass which is right at 1050 and coincided with the best accuracy so it was a nice coincidence. Thats a pretty full load but its just starting to become compressed, like just touching the powder.
My super sonic load for 150 gr bullets is 19.4 gr of cfeblk and the OAL is 2.1, its just starting to compress, a bit more powder and my seating depth will start to have to be moved out.
My limited testing shows that the full/compressed loads really are the best performing so far with the cfeblk.

 

[Seandradamus]

What’s your load with 5 grains, and how fast is it? Reason I ask is I just started, and I’ve been using about 10 gr of cfe blk with 220s and I’m just subsonic from what I can tell (they were cracking at around 12 gr)

My loads Which I carefully worked down to are
5.4g Bullseye with a 190 CC @ 1.570 LTO
Avg speed 1075
6.1g Unique is practically the same.
For heavier bullets you need more powder for the
Same speed ....6.5g of Bullseye behind a 225 hornady avg is 1045 fps also very accurate in my experience it loads very similar to the 220 smk
, I wanted the quietest load possible and see if I could find accuracy, hence the small amounts of pistol powder.
I also liked imr 4227 for the 190s , A bit louder but
Great sds and accurate 9.4g behind the 190 nosler.
Disclaimer ( These loads are safe in my rifle,not necessarily in yours. Fast pistol powders can create a lot of pressure with small changes especially behind large heavy projectiles.)

 

[Strykervet]

Probably on par or slightly better than with a 200gr 45 ACP round.

No, most certainly not. It's much better.

There is a shift in POI vs. supers of course, but the drop isn't as bad as you'd think and due to the high BC it's pretty consistent. The round simply doesn't lose much velocity downrange. I was shocked the first time I used it, totally sold on .300BLK THAT DAY. The BDC scopes aren't really a wise option FWIW, because the scales don't always line up and the scale for the subs is far to short --it'll go much farther than 150m. A better optic IMO/E is a simple Mildot with a sticker on it with your adj. Or just use the appropriate dot.

As for loading semi .300's there are actually only a few powders recommended by mfg.'s, but I suppose it depends more on your system. I tend to stick to the recommended stuff AA makes.

 

[deersniper]

 

[Strykervet]

View attachment 6869849View attachment 6869849

Problem with those reticles is since they use two different loads they depend on you using the load they were designed for, plus they are calibrated for a certain length barrel, usually 16". You can zero one side fairly well, but it'll throw off the other. The wind scale is useless too, because a lighter super will be affected differently than a heavier sub. I guess it depends on how accurate you wanna be too.

Is that a Leupold reticle? The ACOG reticle, and I have the book right here, only goes to 100m for subs. The stadia goes farther for supers, but the subs won't line up. Even then it's calibrated for a 16"bbl., 115gr. supers and 220gr. subs.

I use 125's and 135's for supers and 220's for subs in 8.5" bbl's. If I zero good for the supers, my subs will be off. So it got stuck on a 16" and I have some 115's for it.

I swear based on experience that a mildot just works a lot better. Now if you could have a reticle custom made for your rifle, your rounds, that'd be nice. I was really into these reticles too until I realized all this, and the longer the shot the more noticeable the difference, of course.

FWIW, the ACOG works "okay" because the super scale is what it's based on, only goes to 600 which is about the max. useful range of this round anyway, and likely why the sub scale is only 100m (though it's good for much farther). This limitation reduces tolerances between supers and subs though and helps make the reticle a little more accurate for a dual setup like this. YMMV.

 

[Badfinger]

I only shoot the 300 subsonic and found 220 gr bullets with Accurate 1680 works the best and quietest for me.

 

[Strykervet]

I only shoot the 300 subsonic and found 220 gr bullets with Accurate 1680 works the best and quietest for me.

1680 is one of the recommended powders for loading subs in a semi. It's what I use with 220's. There are only like 2 or 3 powders that are recommended for loading subs in semi's FWIW.

Most folks use 125's for supers but I read that 130SMK's (or is it 135? I'd have to go look...) has a higher BC and the most KE of any other .300BLK round. So I started to switch to those before everything got put on hold.

 

[Badfinger]

Yeah, I know about the hold. When you're going through Hell, don't stop!

 

[Strykervet]

Yeah, I know about the hold. When you're going through Hell, don't stop!

Roger that!

 

[deersniper]

Problem with those reticles is since they use two different loads they depend on you using the load they were designed for, plus they are calibrated for a certain length barrel, usually 16". You can zero one side fairly well, but it'll throw off the other. The wind scale is useless too, because a lighter super will be affected differently than a heavier sub. I guess it depends on how accurate you wanna be too.

Is that a Leupold reticle? The ACOG reticle, and I have the book right here, only goes to 100m for subs. The stadia goes farther for supers, but the subs won't line up. Even then it's calibrated for a 16"bbl., 115gr. supers and 220gr. subs.

I use 125's and 135's for supers and 220's for subs in 8.5" bbl's. If I zero good for the supers, my subs will be off. So it got stuck on a 16" and I have some 115's for it.

I swear based on experience that a mildot just works a lot better. Now if you could have a reticle custom made for your rifle, your rounds, that'd be nice. I was really into these reticles too until I realized all this, and the longer the shot the more noticeable the difference, of course.

FWIW, the ACOG works "okay" because the super scale is what it's based on, only goes to 600 which is about the max. useful range of this round anyway, and likely why the sub scale is only 100m (though it's good for much farther). This limitation reduces tolerances between supers and subs though and helps make the reticle a little more accurate for a dual setup like this. YMMV.

This is the Leupold reticle. I have one a 16" and one on a 9". Haven't shot the 9 yet but on the 16 with 220s and 125s, it is good enough for me. Not accurate enough for groundhogs but good enough for hits on steel out to 300 with subs and 600 plus with supers.

 

[Badfinger]

What kind of drop are you seeing at 300 with subs assuming your zero at 100? I also have a 9 and a 16.

 

[deersniper]

Not sure. I just use the reticle

 

[TheGrrrrr]

Shooting S&B 200gr out of a 9" Springfield Saint Pistol running Aimpoint PRO with Vortex 3x magnifier. I keep it zero'd at 50yds and just happen to be in a lane that let me send out to 300yd steel. For fun I walked about 5 shots into the target and found a good hold spot for the red dot. It was a lot of fun dropping them in for a ping. Once I found the hold spot, I was hitting steel at about 40% rate. Actual hold spot was just left of the red arrow tip. I snapped the photo to try and remember the drop at 300yd.

 

[LucasJ1990]

Shooting S&B 200gr out of a 9" Springfield Saint Pistol running Aimpoint PRO with Vortex 3x magnifier. I keep it zero'd at 50yds and just happen to be in a lane that let me send out to 300yd steel. For fun I walked about 5 shots into the target and found a good hold spot for the red dot. It was a lot of fun dropping them in for a ping. Once I found the hold spot, I was hitting steel at about 40% rate. Actual hold spot was just left of the red arrow tip. I snapped the photo to try and remember the drop at 300yd.
View attachment 6980940

I wish people would show pics like this more! That is crazy! I love it!

 

[jrpilot]

What kind of drop are you seeing at 300 with subs assuming your zero at 100? I also have a 9 and a 16.

Im at 35 MOA at 300 with a 50yrds zero. I just dial it up and 300 is easy.

 

[Doc68]

I had no issues in florida with 300 blk at 300yds with 208 amax. Found that a crimp made me have better standard velocities. Less spread overall. Was shooting a 10.5" barrel with sdn 6 supressor on it. Had a 2-7 optic that was super and subsonic the Burris P300. Zeroed at 50yds and target was a steel plate the size of a chicken. 90%+ hit rate.

 

[Snuby642]

I run spife's load as well with the hornady 220 rnfb and a slight crimp 2.1 col 12.1 cfe blk.

10 gr over a 220 RN should be at the low 900 fps area I think based on my testing so, yes, they will be very quite but still a good ways from cracking. My load is 12.1 gr cfeblk in federal brass which is right at 1050 and coincided with the best accuracy so it was a nice coincidence. Thats a pretty full load but its just starting to become compressed, like just touching the powder.
My super sonic load for 150 gr bullets is 19.4 gr of cfeblk and the OAL is 2.1, its just starting to compress, a bit more powder and my seating depth will start to have to be moved out.
My limited testing shows that the full/compressed loads really are the best performing so far with the cfeblk.

 

[SniperGod]

I've done test after test with 300 blk out to 500 yards. The biggest issue is your SD and ES added to your moa.
Let's say you can shoot 1 moa but have a ES of 20. 1moa @ 500yds is 5 inches but the high vs low ES @ 500 is 15 inches. So your looking at a 20 inch group. And to get very technical because you're shooting subsonic your bullet will be in the air 2 to 3 times longer than a supersonic bullet so you will have to account for spindrift in Coriolis effect. All in all it's super fun just not very practical. But I still do it.