Subsonic ammo
- Thread starter tate1976
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Heavy on the bullet, light on the powder. It should be labeled subsonic if that’s what it is. We shoot a lot of 300 BO subsonic reloads, not sure if they make much 308 subsonic.
Discreet ballistics subsonic 308 is very good.
Lapua has a 200gr subsonic round that is pretty good as well.
308 Win 175 Grain Subsonic
At ATOMIC Ammunition, we know that the only way to make the best handgun ammunition in the world is to start with the best components available.
www.atomicammunition.com
This stuff is legit.
Here is a further 'tip' if you are reloading. Powder shift is definitely a thing. It will probably be a lot more of a thing in 308 because of the bigger case.
I apologize in advance if you are already familiar with all of this. But it goes like this... with really light loads and a lot of space left in the case the powder can/will move around a lot. The exact same charge with the same bullet out of the same gun... one will be nice and be totally subsonic. The next will launch well into supersonic range. This happens merely because of the orientation of the powder in the case.
With a gas gun you need to have enough energy to run the bolt back and forth as you fire. In a bolt gun this is not a concern. If you use really big bulky powders you can make subsonics out of all kinds of grain weight bullets.
Another thing you have to look out for is that (again with a gas gun vs bolt) is that I have found that even though the bullet is flying subsonic with some powders in a gas gun the bolt opens while the powder is still expanding and it creates a LOUD port pop. I've had my ears rung from 'subsonic' ammo before. With a bolt gun you don't need to worry about that.
I apologize in advance if you are already familiar with all of this. But it goes like this... with really light loads and a lot of space left in the case the powder can/will move around a lot. The exact same charge with the same bullet out of the same gun... one will be nice and be totally subsonic. The next will launch well into supersonic range. This happens merely because of the orientation of the powder in the case.
With a gas gun you need to have enough energy to run the bolt back and forth as you fire. In a bolt gun this is not a concern. If you use really big bulky powders you can make subsonics out of all kinds of grain weight bullets.
Another thing you have to look out for is that (again with a gas gun vs bolt) is that I have found that even though the bullet is flying subsonic with some powders in a gas gun the bolt opens while the powder is still expanding and it creates a LOUD port pop. I've had my ears rung from 'subsonic' ammo before. With a bolt gun you don't need to worry about that.
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Awesome. Thank you for the info. Probably won’t reload for it right but was just curious on what they do to make it subsonic
What is your twist rate?
Some subs have high twist required to stabilize them.
Some subs have high twist required to stabilize them.
7,62 × 51 – FMJ SUBSONIC (V341562US) – 200 GRS – Sellier & Bellot
www.sellier-bellot.cz
Super quiet in my 5R Remington 700
just make sure to check it in your rifle for keyholing at 2-3yds. to make sure you don't get a baffle strike before you put your
suppressor on. It is amazingly quiet on a 24" barrel.....
I sold my 5R but I still have some ammo, I'm going to try it in my 16" AR10 when I can get to the range with a spare 6x scope I have
and see how it does, I already know it won't cycle the action but for close in targets it might just be a compliment to my .300BO subs.
with a little more energy.
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Wow, look at that pressure spike with Trail Boss in that 308 load. Almost double the pressure of a couple of the other loads, hot dang.
Most sub sonic twist rates are 1:6 to 1:8. With some super short barrels at 1:5 twist.
Personally, I would never do 308 Win sub sonic. Like mentioned, powder to case ratio.
Doesn't matter if it's 308 Win or 300 BLK. A .308 diameter bullet weighing 190gr - 220gr going 1,000 FPS is the same out of both rifles.
If it's a bolt gun, the 308 may not be too bad, but I would not want to try and make it cycle in a semi auto. That's what 300 BLK is good at.
Personally, I would never do 308 Win sub sonic. Like mentioned, powder to case ratio.
Doesn't matter if it's 308 Win or 300 BLK. A .308 diameter bullet weighing 190gr - 220gr going 1,000 FPS is the same out of both rifles.
If it's a bolt gun, the 308 may not be too bad, but I would not want to try and make it cycle in a semi auto. That's what 300 BLK is good at.
200 gr S&B would not stableize in my Remington r5 10” twist barrel. Had baffle strikes first three rounds.
Be very careful with 10” twist barrel and subsonic ammo.
Rad
Be very careful with 10” twist barrel and subsonic ammo.
Rad
Sounds like I need to call some ammo places and get the scoop. If it doesn’t work out the. It’s no biggie. It’s just for plinking anyways so full loads aren’t any issue
Most heavy subs in 300 blk call for a 1/7 twist and shooting them out of a 308 cartridge is not going to change that.
I have not kept up with sub ammo for a 308 since we have several blackout guns but check manufacturers requirements for twist.
I never found a 1/ 10 twist load for the 308 in any books.
Discreet Ballistics
INTENDED FOR BARRELS WITH A 1:10 OR FASTER TWIST.
The Discreet Ballistics 308 Win Selous Subsonic Hunting load was conceived as part of a two load system. This load is intended for short barrel (<20″) bolt action rifles with 1:10 or faster twist barrels. This round will also function with semi auto platforms, but will require manual cycling of actions. This load incorporates a machined copper 30 Caliber projectile (the Selous bullet) which expands at subsonic velocities above 750FPS. The Selous projectile uses state-of-the-art ballistics modeling software with the goal of maximizing stability at subsonic velocities.
INTENDED FOR BARRELS WITH A 1:10 OR FASTER TWIST.
The Discreet Ballistics 308 Win Selous Subsonic Hunting load was conceived as part of a two load system. This load is intended for short barrel (<20″) bolt action rifles with 1:10 or faster twist barrels. This round will also function with semi auto platforms, but will require manual cycling of actions. This load incorporates a machined copper 30 Caliber projectile (the Selous bullet) which expands at subsonic velocities above 750FPS. The Selous projectile uses state-of-the-art ballistics modeling software with the goal of maximizing stability at subsonic velocities.
that's odd but I only fired a few to check for stability which it was ie; no keyholing, and never did again. I was not aware of the twist rate anomaly in the longer barrels as subs have obviously been used in .308 successfully by many people.
Are there any 308 Subs that will cycle a 308 auto? All of them I am aware of were marketed as single shot rounds.
If you tune/build your gun to cycle them I'm sure it can be done. You'd probably need a longish dwell length barrel, large gas port, high backpressure suppressor, lightweight bcg/spring/buffer combo.
Have you seen it done? I have not. 308 subs are weird animals for autos. If you were able to tune it to work I have doubts about how well it would then handle supersonics. There is a reason the Blackout/Whisper is so popular in this role and even the new 8.6 Blackout has a smaller case with heavier bullets sticking to a similar formula as the 300. All that extra space in the case makes it a pretty tough thing to do.
I'm sure I could make one but it would 100% be shit without changing gas setting and then swapping to a low back pressure can. It wouldn't be like 300 blk. Idk I'm sure you could find a set up that wouldn't be horrible to handle both but you would still need to adjust gas settings and probably be using a low/lower back pressure can from the start.
I've read reports of people making them function subs but actually seeing them, no. It's not worth the hassle to figure it out one that handles both although I think I probably could. It would probably take a 16" carbine gas with a large port and adjustable gas block, lower back pressure can. You may have to do some custom gas length and mess with the barrel length.
Exactly. My Seekins 300 BO is 1:7.
Never understood the .308 subsonic. Not knocking it, just don’t get it. I don’t feel like it’s meant for it. I mean, why not .300 WM subsonic or .338 lapua
I didn’t build it specifically for subsonic ammo. It was more of a curious thought. Never shot anything subsonic so I figured I ask
Right on. I understand. Nothing wrong with messing around with it. I shoot my 300 blk at 250 yards
It's for people that are stuck with that gun which is a lot of police military types. That's why you see subs listed all the way up to 50 bmg. Dedicated subsonic guns are pretty cool but also extremely limited for what they can be used for.
SG Ammo was selling the 240gr stuff for years and finally just sold out of it. I’m guessing it was something special they were trying to move as they sell a LOT of IMI rifle ammo. I’ve never seen the 200gr or 220gr stuff for sale anywhere.
In my 1/10 Rem700 SPS the stuff gave a 3.5” group at 50m at showed signs of instability. I couldn’t even keep 3 rounds of it on a B-8 repair center at 100m. I’m going to try it in my MWS but I’m not hopeful.
Ek
I have a load I use in my MDRX that will cycle (just on the edge of short-stroking)
uses a hornady 220gr Round Nose SP over 10gr of Trail Boss. since I live in the People's Republic of Marylandistan fun is not allowed and I can't have the 16" 300 blk barrel kit, I made this work. (we have a dumb 29" OAL requirement for centerfire semis)
Incase Imgur shits the bed: 2.760 COAL, 10gr Trail Boss, Norma Brass, CCI LR primers, part # for the bullet is hornady 3090
uses a hornady 220gr Round Nose SP over 10gr of Trail Boss. since I live in the People's Republic of Marylandistan fun is not allowed and I can't have the 16" 300 blk barrel kit, I made this work. (we have a dumb 29" OAL requirement for centerfire semis)
Incase Imgur shits the bed: 2.760 COAL, 10gr Trail Boss, Norma Brass, CCI LR primers, part # for the bullet is hornady 3090
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But still half of the max operating pressure of the .308. If someone is going to load the .308 at sub velocity then Trail Boss is the best way to go.
