View Full Version : Recreate S&B .308 200gr Subsonics
I would like to replicate this round as it has performed great and is very quiet. Does anyone know what powder and/or charge this ammo uses? If I can find some more for sale I will pull one apart and weigh the charge but as of now I can't find any more.
The only subsonic .308 recipes I've seen use TrailBoss and a lighter bullet.
http://img.tapatalk.com/d/14/03/06/vedydy5e.jpg
Shouldn't be hard to work this load up with Trailboss. I've shot the 175s with like 10.8 grains???
Maybe start at 10.0?
I've done 220 gr soft points in .308 with about 10.0 I think.
Thanks for the info.
At the moment the only pistol powders I have on hand are W231, H110, and A1680. I haven't seen Trailboss on the shelves for a very long time. I might have to go begging to my friends who use it and see what I can work up.
Really should be Trailboss due to the large case volume. Make those buddies of yours loan you some.
Hodgdon has a few light loads in the 308 data.
Be careful of using just any old powder you have and bringing the charge weight down. Most powders are susceptible to detonation.
I know there are TiteGroup loads out there and a few others, but IMO you are just begging to have powder not ignite evenly due to the primer flame going over the top of it with such a tiny load of a fast powder like TiteGroup.
I wont load any 308 subs except TrailBoss. Only way to roll.
And that bullet in those looks like it MIGHT be a 200g SMK or possibly the Lapua subsonic 200g(although I doubt this).
Ive shot subs from 150g FMJBT's up to 220g SMK's out of a 10 twist rem 700. The 180g RNFB(which are impossible to find) are about the best since they are a flat base and supposedly fly better than the BT bullets do. The Lapua 200g subsonic bullet also has promise although I havent played with them yet. Its kind of a modified boat tail design.
Ive shot subs from 150g FMJBT's up to 220g SMK's out of a 10 twist rem 700.
I can tell you 220 Sierra hunters don't quite make it in 1/12. ;)
They hit paper at 100 with about a 30 degree yaw.
I can tell you 220 Sierra hunters don't quite make it in 1/12. ;)
They hit paper at 100 with about a 30 degree yaw.
No way would I attempt the 220 SMK's in a 12 twist LOL. They are barely stable in the 10 twist according the JBM.
No way would I attempt the 220 SMK's in a 12 twist LOL. They are barely stable in the 10 twist according the JBM.
After seeing what they did Sub, I cranked them up to super, and they shot about 1moa. I could not believe it.
I know there are TiteGroup loads out there and a few others, but IMO you are just begging to have powder not ignite evenly due to the primer flame going over the top of it with such a tiny load of a fast powder like TiteGroup.
I wont load any 308 subs except TrailBoss. Only way to roll.
And that bullet in those looks like it MIGHT be a 200g SMK or possibly the Lapua subsonic 200g(although I doubt this).
Ive shot subs from 150g FMJBT's up to 220g SMK's out of a 10 twist rem 700. The 180g RNFB(which are impossible to find) are about the best since they are a flat base and supposedly fly better than the BT bullets do. The Lapua 200g subsonic bullet also has promise although I havent played with them yet. Its kind of a modified boat tail design.
As per Hodgdons own data Titegroup is NOT detonation sensitive. It would be safer than trailboss in any low charge/large capacity case.
I scrounged up some old Speer 200g flat base bullets. I still haven't managed to locate any Trailboss.
A friend tried some loads with Titegroup and said he thought there were issues with such a small charge. I think I will hold out for some Trailboss.
Update time....
I haven't been able to locate a single grain of Trail Boss to try any loads, but I did manage to find a couple more boxes of this ammo at a local shop. I decided to sacrifice one for science and here is what I learned....
http://i.imgur.com/oS7tkzX.jpg
All rounds were very nice looking and had very uniform cartridge length, average was 2.785"
http://i.imgur.com/rIaPmvT.jpg
Lots of primer sealant
http://i.imgur.com/ZP2NJ7a.jpg
200 grain HPBT with sealant
http://i.imgur.com/r1A3ESC.jpg
The charge was 9.7 grains of some kind of square powder
http://i.imgur.com/pgnk2rH.jpg
Its hard to tell in the picture, but one side is silvery and the other is a duller gray with a bit if a green tint.
I was intrigued by the powder. Since these are made in the Czech Republic I would guess its something we don't have over here. Anyone have any clue what this powder is or have you ever seen it before?
Wow! That is interesting. Appears that powder was manufactured as a sheet and ginsu'd into squares. Never seen anything like it. Thanks for posting.
I just spun up some 220 gr Sierra Pro Hunter soft points two days ago. I've got the subsonic bug again myself.
If you were near me, I'd load you some Trailboss. The half pound I have left will last me over a year probably.
Ya, powder is still pretty much unavailable out here in the Willamette Valley. If the stars align you can get some rifle powder but still haven't seen any pistol. I talked to a guy at a gun shop who had just taken a trip to the Midwest and he said the powder supply situation was better there.
Even though it's not ideal, I might mess around with the Titegroup subsonic loads that the Hodgdon data lists to see how big of a problem the powder ignition issues that people have mentioned are. A friend loaded some for his .308 and they seemed to work just fine.
I also subbed in WLRM primers. Large rifle magnums... I'm hoping they work, because I have no other use for them. I think I have Remington Large Rifle Mags too.
If you see any noticeable differences with the magnum primers report back. I've been wondering about using them for subsonic loads.
Another small update.....
I finally found some TrailBoss on the shelf!!!!
This week I will load a couple test rounds with the 200grn soft point, flat base bullets I've got. I think I'll start off trying 9.8grns and 10grns of TrailBoss.
On a side note, has anyone ever loaded bullets that are tarnished? Did it affect bullet stability or accuracy? Some of these old bullets have some heavier tarnish on them that worries me slightly. You can just barely feel it, but for the most part they still feel smooth.
31175
Anyone think I should be worried about it? I was thinking about tumbling them to see if that cleaned them up, thought that might mess up the soft point though.
Another side note,
I shot a few more boxes of the S&B subsonic ammo and noticed that many of the primers had popped out of the case a little. I measured a few and they were about .013"-.017" out. It's hard to see, but here is a picture.
31177
Seems weird for a subsonic load to do this. Never had a primer do this with any other load in this gun, just the S&B subsonics. Any thoughts?
This is just a swag! but the cause of the popped primers might be "bridging" of the powder burn -that is caused by the flash from the primer igniting the powder at the flash hole and the bullet base at the same time, and causing a pressure spike- I did see a person loading subs and he would drop the charge into the case and then tear off a small bit of cotton ball and stuff it into the case to hold the powder charge at the flash hole to prevent this, he also showed some chrono readings and the SD's and extreme spreads dropped when he used the cotton.
I have got my application in for a sbr and considering chopping of a 7.62x39 barrel to 10'' and shoot subs out of it, I have fired nosler bt's out of it and got reasonable accuracy so I believe at close range .308 dia. 200 - 220 gn bullets will do ok.
btw - the 7.62x39 is a AR type rifle not AK.
waveslayer
03-05-15, 16:05
This is just a swag! but the cause of the popped primers might be "bridging" of the powder burn -that is caused by the flash from the primer igniting the powder at the flash hole and the bullet base at the same time, and causing a pressure spike- I did see a person loading subs and he would drop the charge into the case and then tear off a small bit of cotton ball and stuff it into the case to hold the powder charge at the flash hole to prevent this, he also showed some chrono readings and the SD's and extreme spreads dropped when he used the cotton.
I have got my application in for a sbr and considering chopping of a 7.62x39 barrel to 10'' and shoot subs out of it, I have fired nosler bt's out of it and got reasonable accuracy so I believe at close range .308 dia. 200 - 220 gn bullets will do ok.
btw - the 7.62x39 is a AR type rifle not AK.
I think you are spot on, how much does your powder fill the case? And what's your case capacity?
The information I shared was a posting on u-tube and about loading subs in a 300 blk. [I do not recall the name of the poster-and apologize for possibly leading anyone think I have already tried this]. I have not tried the load yet, right now my AR-K is a 16' carbine 1-10 twist, so still loading at regular velocities, waiting on form 1 approval before moving forward on mods to the barrel. I'm thinking it will work being as the powder charges are similar between the 7.62 and 300blk. and if it does notwork -then Ihave a excuse to build a 300 blk:dance3:
Thanks for the input!
The picture I posted with popped primers was factory S&B subsonic .308. The rounds use the same funny square powder that I have seen them use in some of their shot shells.
I loaded a few test loads using Trailboss but have not had a chance to test them yet. Hopefully will get a chance to borrow a chronograph this month.
The Trailboss is a little "fluffier" than the S&B powder and takes up more of the case. I'm hoping this will keep this from happening in my loads.
Well thanks for the info on Trailboss, I really wasn't sure what powder to try but that sounds like a good one to try first -providing I can find it, really want a fast burning powder since when I do try subs it will be with a 10'' barrel.
I finally got some time on my friends chronograph and tested a couple loads. It's not a very scientific test but its something.
Gun: Ruger Gunsite Scout, 16.1" barrel, 1:10 twist
Bullet: Speer "Hot-Cor" 200gr soft point flat base
Powder: Trailboss
Primer: WLRM
Air Temp: 53 degrees F
Altitude: 850'
Keep in mind these were only 3 shot groups since I had limited supplies to make test rounds with. All stabilized fine in my Ruger Scout Rifle.
Charge: 10.5gr
Avg Velocity: 932fps
Charge: 11gr
Avg Velocity: 937fps
Charge: 11.5gr
Avg Velocity: 969fps
The higher the charge the smaller my velocity spreads were, but they were still pretty big. The 10.5gr load was 127fps and the 11.5gr load had the smallest at 52fps. Accuracy was also best with the higher charge. I think 11.7gr-12gr might be about right.
The Sellier & Bellot factory ammo had an average velocity of 1015 and an extreme spread of only 11fps.
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