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Subsonic .308 load data? another question :) 2

benbangui

Sergeant of the Hide
Full Member
Minuteman
Apr 5, 2010
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Someplace, MUrica
I got Varget and 168 smks and large rifle primers. I can't find any load data for this components... Do I need to get a heavier bullet?
Please educate me :) thanks!
 
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I got Varget and 168 smks and large rifle primers. I can't find any load data for this components... Do I need to get a heavier bullet?
Please educate me :) thanks!

Can't grant you a degree, but strongly suggest you try search function and "Trailboss"
 
Can't grant you a degree, but strongly suggest you try search function and "Trailboss"

I didn't know what that was at first but after googling it are you talking about using different powders? I live in HI so access to powders are very limited. But more then just powders are there any places I can look up load data on subsonic .308?
 
I looked up load data on hodgdon.com and found some loads that only used 8+ grains of powder that shot around 1000fps but they were using powders that I can't get my hands on...

Currently I only have varget and imr 4320.

HELP :)
 
The problem with subsonic 308 is case capacity. Trailboss is flaky and fills the case with the considerably less powder you use for subsonic. I've been looking for Trailboss for this exact same reason as well but it's hard to find, especially now.
 
I've seen sub loads using Unique, red dot, and a few other pistol type powders. I've only used Trailboss. Never seen any specs using the rifle powders you mention. Not that they won't work if you load them down enough, but I hear that many powders have some very undesirable results if downloaded excessively. I prefer to learn from other's mistakes....

The heavier the bullet the better. Faster rifling twists will usually help. Round nose/flat nose have more effect on game. I'm assuming this is for a suppressor--if so, then thoroughly test your loads for stability WITHOUT the suppressor. Shoot through cardboard about a foot away from the muzzle to make sure you get nice round holes. Do the same at 25 50 100 yds. If hunting, limit shots to 75 yds or less. My 20" AR-type 308 POI is about a foot low at 100 yds. The severely anemic ballistics of subs will not expand hunting bullets at all, so you need to rely on heavy weight and a flat nose bullet for terminal effect. You CAN buy bullets that will expand, but they are very expensive. IN MY OPINION AND FOR MY PURPOSES, subsonic rounds are only useful for suppressor demonstrations or shits and grins. I prefer full power ammo for any other use such as hunting. IME, it takes more than 1050 fps to make any normal hunting bullets perform properly. I'll put up with the sonic crack for any serious use. But subs are fun and you will learn a lot messing around with them.
 
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Loading Varget and 168SMK's for subsonic can cause some problems. You need a different powder. And honestly a heavier bullet would be better (180gr works well). Read up on Secondary Explosion Effect when loading subsonics. You other option is to get some brass or aluminum bar stock and lathe a 308 case with a smaller interior volume and small rifle primer pocket. But event then Varget may not work for you.
 
The whole point to shooting subsonics is to use the heaviest bullets possible in order to maintain the greatest amount of energy on target. For shooting with suppressors it makes a lot of sense to shoot subs. I don't know if you're allowed suppressors in Hawaii and if not then don't waste your time with subsonic 308. The case capacity is too large to be a very good subsonic cartridge. Even with trailboss its not all that accurate. Depending on your rifles twist rate you may be limited to lighter bullets and what good is a 150gr when you should be shooting 240's. You need a twist rate of 1-8 or faster to make 220-240gr bullets dependably stable. If you really want a 30 cal subsonic look to the 300 blackout which is more than suited for loading subs. There is factory ammo out there with 220gr subsonics. Its much more well suited for the subs and will handle supersonics as well. Pretty decent round for all around short range use.

Frank
 
208 AMAX and trailboss is what you need. Atleast it works fine from one guy I know. Hope this helps. Make sure you got enough twist and check before shooting with suppressor.
 
The heavier the bullet the better the performance usually due to more moving mass to carry momentum. Try running a 175 or 180 if your gun can stabilize them.


Look at the 45 ACP vs 9mm for instance.
 
Do not use the Varget to load subsonics, that would be a recipe for disaster as loading too low of a charge can be just as bad as an over-charge. For subsonic you need to be using an appropriate powder such as one of the pistol powders.

By far the best and safest subsonic loads I have played with are made with Trailboss. I load 200gr SMK over 10.5gr of Trailboss, which nets me an average velocity of 1042 FPS out of a 20" barrel with a 1:10 twist. You can use lighter bullets and will be fine, just follow the advice of IMR and work backwards until you reach your desired velocity.

Some will drill out the primer pockets, use different primers, etc. I do not find that it is necessary after experimenting with the subsonic loads.
 
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Thank u everyone for your imput!!! I will do more research on what you guys gave me and come back with my results or more questions. You guys already helped a lot! Thanks!
 
IMR SR 4759 will work as well as Trailboss, but with the lighter 168's you have, Trailboss is what you want. I think there are several loads I posted in the reloading data section several years ago.
 
So I won't be able to get my hands on any trail boss for a couple months. In the mean time I have read stuff about people using pistol/shotgun powders to light load. But at same time everyone says it's unsafe. But the ones that say it is unsafe also have not experimented with it. Has anyone actually loaded some up themselves?

I Don't wanna do something unsafe obviously but the concept makes sense to use shotgun powder. I just don't wanna try it based of a "good concept" lol

So has anyone tried this? :)
 
So I won't be able to get my hands on any trail boss for a couple months. In the mean time I have read stuff about people using pistol/shotgun powders to light load. But at same time everyone says it's unsafe. But the ones that say it is unsafe also have not experimented with it. Has anyone actually loaded some up themselves?

I Don't wanna do something unsafe obviously but the concept makes sense to use shotgun powder. I just don't wanna try it based of a "good concept" lol

So has anyone tried this? :)

I loaded some with Unique for 223 a very very long time ago (early 80's?) but can't find those specs now. Had no mishaps, and back then I was really ignorant of what the sonic crack sounded like-so I'm not sure if they were actually subsonic or not. I had no suppressor and the only chronos available were way too pricey for a starving 22 yr old with a family. Have you searched back through these forums? I'm sure there's some data somewhere here for something besides TB powder. Also there's another forum called silencertalk where you may find some specs.
 
Yea I live in HI so powders have to be boated over. And the store that said they "might" be able to order me some said they just did a order so they wouldn't be doing one for another 2 months. Which actually means I won't get it for 3... The sacrifices to living in HI...

Yea I looked in this forum. But not crazy far back. I can do some more research. But I'll defiantly try silencertalk thanks for help! :)
 
So I won't be able to get my hands on any trail boss for a couple months. In the mean time I have read stuff about people using pistol/shotgun powders to light load. But at same time everyone says it's unsafe. But the ones that say it is unsafe also have not experimented with it. Has anyone actually loaded some up themselves?

I Don't wanna do something unsafe obviously but the concept makes sense to use shotgun powder. I just don't wanna try it based of a "good concept" lol

So has anyone tried this? :)

I've been loading subsonics since '95 (pre-Trailboss) and of course you can use those powders. For over 7 years I used Hornady 220's over Greendot (~10.5 grains if I remember correctly) in a 18", 1/10" twist Kreiger barreled 308. The sound signature is incredibly quiet and the accuracy is outstanding---IF you remember to raise the barrel and tap the powder against the primer, as well as developing a good dope for different temperatures. Out of 6000 or so rounds, I never had a secondary detonation; but hey out of 4 hookers and 34 last calls, I never got anything Ajax couldn't scrub off either. Your results may vary...

Almost forgot...start with Greendot and Unique. Red and Blue Dot both were too hot to get consistent.
 
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I've been loading subsonics since '95 (pre-Trailboss) and of course you can use those powders. For over 7 years I used Hornady 220's over Greendot (~10.5 grains if I remember correctly) in a 18", 1/10" twist Kreiger barreled 308. The sound signature is incredibly quiet and the accuracy is outstanding---IF you remember to raise the barrel and tap the powder against the primer, as well as developing a good dope for different temperatures. Out of 6000 or so rounds, I never had a secondary detonation; but hey out of 4 hookers and 34 last calls, I never got anything Ajax couldn't scrub off either. Your results may vary...

Almost forgot...start with Greendot and Unique. Red and Blue Dot both were too hot to get consistent.



So basically just no shooting downhill then? :)
 
Slight declines were fine. When we would sit in our box stands to shoot hogs, we'd just tap the powder to the primer and gently lay it back down. That was good enough to keep the 1/2" 100y groups, but we still took shots without all the fuss and would get 2-3" vertical stringing groups instead. Almost forgot, I always used magnum primers for sub loads.
 
Have you tried drilling out the flash hole a little?

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