Powder choices for subsonic 308?

[Elkins45]

I have a user-serviceable silencer that I shoot a lot of 300 blackout cast through. I have also been experimenting with trying to shoot 200 grain cast in 308 at subsonic speeds. My initial experiments have been with Trail Boss because it is so bulky and takes up a lot of space, but accuracy is less than I expected with the particular bullet/rifle combo.

It's a bolt gun so I don't have to worry about cycling the action. What powders are most commonly used for subsonic 308 loadings with good accuracy?

Thanks for any info

[jcren]

I have better accuracy with pistol powders in my 3006 230 grain plinkers. Try the standard 10 grains of unique and see what you think.

[runfiverun]

you'd probably wat to back that down from 10 grains.
I would be a little more inclined to use 6-7 grs of bulls-eye myself.

[Artful]

Try titegroup or clays if you don't like trailboss - one of the things I did to get trailboss to work really well was to restrict the capacity so I had 100% loading density - David did his CNC magic and made a small batch of machined 308 cases that work great. It was worth the $8 each price to stop looking for the perfect subsonic round.

Here a link or two for you to look at
http://members.shaw.ca/cronhelm/DevelopSubsonic.html
http://www.quarterbore.net/forums/showthread.php?t=280&page=3
http://www.loaddata.com/articles/PDF/LD-36%20Haviland%20LR.pdf

[fecmech]

I would second the Bullseye@ 5-6 grs or possibly Red Dot.

[RU shooter]

Another vote for 5-6 grs. Of bullseye .

[Shooter6br]

SKS shooting 200g 314299 with Red Dot http://members.shaw.ca/cronhelm/762Page.html

[gwpercle]

Might want to try starting with:
8.0 grains 700X
10.0 grains Red Dot
10.0 grains Unique
11 grains Green Dot
12 grains Herco
what powders do you have/can you get ?
Gary

[Wardo1974]

Some of these loads seem too hot to be subsonic.

I personally love Unique for this purpose. I have a plinking load for my .38-55 with a 250 grain bullet, and it's still about 800 feet per second, and it's very accurate. 10 grains would be sending it downrange at 1200-1300.

[Tackleberry41]

I use Solo1000 in my subsonic rifle ammo, but I just have a big pile of it. Most any fast burning pistol powder will work, the charge simply needs to be adjusted for your rifle and load.

[Victor N TN]

A friend of mine uses 700X, Unique and / or Green Dot.

I hope this helps.

[762 shooter]

My 180 grain Hornady soft points with 11.0 grains of Trailboss do a leisurely 1050 ish out of a 17" barreled Ruger Gunsite with a can. Crazy quiet.

2" at 100 yards. This accuracy may not be that interesting to some. I guess it would be interesting if you were a coyote and you couldn't understand why your buddy just fell over dead for no reason.
762

[Victor N TN]

This accuracy may not be that interesting to some. I guess it would be interesting if you were a coyote and you couldn't understand why your buddy just fell over dead for no reason.
762

That would get MY attention.

[fecmech]

8.0 grains 700X
10.0 grains Red Dot
10.0 grains Unique
11 grains Green Dot
12 grains Herco
I'm pretty sure none of those loads are subsonic.

[BK7saum]

What alloy are you using? I have a bolt action 300 whisper and cannot use the fast pistol powders with my alloy and the NOE 247. Get nose slump and decreased accuracy. If your alloy is harder enough to take the push from the faster powders, great. If not use a slower powder like aa1680 or 2400 or 4227. However they aren't as quiet as the fast pistol powders. Just a little bit of experience speaking.

[rsrocket1]

http://i270.photobucket.com/albums/jj96/rsrocket1/Shoot/1755f589-3533-41fa-ac93-a732fb372b85_zps374cefb7.jpg

[762 shooter]

rsrocket1,

Is that a 308 Win? Yardage?

That's an impressive group.

762

[Tackleberry41]

The charge required varies alot. That 10g unique load works in pretty much anything, but is not listed as 'subsonic' just the load. My 30-30, only needs 7gr of S1000 to get a 230gr bullet out of a 16in barrel at subsonic. Where my Msoin shooting the exact same bullet needs 11gr. More or less barrel length changes things. And depends on where you live, a load thats fine at my house, gets a 30fps boost going to my friends house, at a lower elevation. You really need a chrony to know where your at.

[Wardo1974]

The good part about using pistol powders is that you only need a tiny amount to get the job done, and aren't position sensitive so you don't have to worry about how it lies in the case or anything. Trail Boss seems a bit silly to me. I don't need a full case of expensive powder when a pinch of Unique works just as well. My 800 fps .38-55 load is only 5 grains.

One day, I loaded it all the way down to 1 grain, and I could still hit pop cans with it at 20 yards at 1 grain! That's a bit too light, but it was still enough to stick into a piece of firewood. 5-8 grains of a pistol powder would do a great job for a subsonic plinker I think.

[rsrocket1]

Range was 50 yards. I was testing 113, 170 and 200 grain bullets with charges ranging from 5 to 10 grains. I think you want to use the very fastest powder you have or can find. I've found that with these light charges, faster powders gave the most consistent velocities. You don't need to worry about too much pressure, slumping bullets or hitting the back of the bullet too fast and too hard with these light loads. Other powders that I've tried in the past that would work well would be Clays, Titewad, Titegroup, Extra Lite, e3, Promo. This was my first attempt into subsonic loads and since Red Dot was my most abundant powder, that's what I used for these tests.

Yes, it's my Remington 788 in .308 that I bought in the early 1980's for $119 new in the box. I've done nothing to the rifle other than remove the iron sights and attach a scope to it. It's a pretty accurate gun. Lee 30 cal bullets are all identical from the base to the front of the driving bands and I've found that when I seat a sized bullet to 0.3" of seating depth, a can feel the front driving band sliding snugly into the throat/leade of the rifle to align the bullet. With the ideal seating depth known, all I need to do is to find the best load for what I want. So even at higher velocities, I can quickly find a good load. The only catch is that the POI tends to move around if I change the velocity drastically. Here are some faster groups.
http://i270.photobucket.com/albums/jj96/rsrocket1/Shoot/0e6d2e93-5a2b-4efb-8889-5f838bed53da_zpsxtmdz3cs.jpg

[762 shooter]

Nice... I'm pretty sure I read somewhere on the Internet that those 788 Remingtons were so accurate that aiming was unnecessary.

I have one I need to wring out. I have a Ranch Dog mold that I bet it will shoot. Too bad it's not threaded.

762

[Elkins45]

Might want to try starting with:
8.0 grains 700X
10.0 grains Red Dot
10.0 grains Unique
11 grains Green Dot
12 grains Herco
what powders do you have/can you get ?
Gary

I'm pretty sure most of the are supersonic except maybe the 700X load. I have a fairly wide selection of the favorites: 231, Bullseye, Unique, Red Dot, 800-X, Power Pistol, 2400, and some others. I bought some Vectan GM3 from Grafs. It has a burn rate similar to AA#5 but is much bulkier. 7-8 grains of that might be a place to start..



What alloy are you using? I have a bolt action 300 whisper and cannot use the fast pistol powders with my alloy and the NOE 247. Get nose slump and decreased accuracy. If your alloy is harder enough to take the push from the faster powders, great. If not use a slower powder like aa1680 or 2400 or 4227. However they aren't as quiet as the fast pistol powders. Just a little bit of experience speaking.

Depending on the application either air cooled wheel weights or quenched wheel weights. I have done some experimenting with pure lead but had the same results you mentioned.