Subsonic 6.8 rounds

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Breeves918

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I have a buddy that is wanting me to load some subsonic 6.8 loads for him. He’s got some Hornady sst 130 grain bullets I was wondering if anyone had any load data for something to start with
 
I would only use Trail Boss , starting at 6.5 gn and work down carefully to approx 6 gn, COL 2.260"

Always check for a stuck projectile, if not sure.

It probably won't cycle a normally gassed AR.
 
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Just my 2 cents. Not Bible but take it for what its worth.

Personally I wouldnt reload anything for a buddy, especially subsonics. If for some reason something doesnt go right, it could potentially end up dangerous for your friend. As a reloader, you know what to think about if you hear a round go off and "it just didnt sound quite right". As a non reloader most people will just shrug that off and load another round and pull the trigger, which could be bad.

But if you still decide to load for him, i would use trail boss and follow hogdons recommendations on how to acheive a max powder charge. They have a formula on their website to follow. Start there and then work your way down "listening for something not quite right"and watch your chrono till you reach the desired speed.
 
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Originally Posted By: Kevinfarmer3456...work your way down "listening for something not quite right"and watch your chrono till you reach the desired speed.
Good point Kevin, you (Breeves) should run your reloads in buddy's gun to work down to a load, with a chrono.
You know what to look for and when to stop.
Any hesitation on buddy's part is reason to move on.
 
Yea I will be doing all the shooting and testing until I find a winner for that exact reason of him not knowing what to look for just not real sure where to start
 


When I want subsonic in an AR I shoot 300 Blackout.
I can buy 120gr to 220gr rounds and low cost. $20/box.
120-140 gr 2300fps. Just buy a new upper.
 
130gr will be hard to make subsonic and cycle. You will have better luck with 180gr and 200gr. Then those bullets are so long they will need a fast twist to stabilize. The Bison 1:7 will be the only one to do that. You can use trailboss or H322 or H4895 as recommended by Bison. I would not start low and work up, with subsonic it's better to start high and work down. Since the 180gr and 200gr bullets are so long, you will be limited by case capacity because the bullet will be so far into the case at mag length 2.295" or shorter. I would start around 2.280", judge what 90% case capacity is, load up a few and see how it goes. If it cycles but isn't subsonic, I'd start reducing .5gr at a time until they become subsonic and hopefully still cycle. 6.8 wasn't really made to cycle subsonic but can be done with some fiddling and the right components. GL.
 
Originally Posted By: willy1947When I want subsonic in an AR I shoot 300 Blackout.
I can buy 120gr to 220gr rounds and low cost. $20/box.
120-140 gr 2300fps. Just buy a new upper.

I'm with willy ^^
 
Originally Posted By: JoeBobOutfittersOriginally Posted By: willy1947When I want subsonic in an AR I shoot 300 Blackout.
I can buy 120gr to 220gr rounds and low cost. $20/box.
120-140 gr 2300fps. Just buy a new upper.

I'm with willy ^^


And Joe Bob's have some nice uppers at a good price to buy.
 


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