308 Subsonics

[SSChameleon]

I'm working on 308 subs. I'm running them through an 18 inch 1/10 barrel. I loaded some 168 grain boat tail with Clays using the data from the Hodgdon website.

I loaded 10 test rounds, then shot 7 rounds from 20 yards without a suppressor to check for signs of key holing. Everything looked good, so put the can on and backed up to 100 yards. Three shots keyhole at 100 yards.

I won't make it back to the range until later this week, and plan to try 50 yards and 75 yards without the can. From those who have experience, what I want to know is:

Is it common or expected for subs to tumble inside of 100 yards?
Is it safe to run these through a can?

[Little Dutch]

I'm a little surprised they keyholed actually. Any idea what the velocity is?

You may try moving up the velocity a little or move to a heavier bullet.

I don't have a lot of experience with subsonic .308, but I use 180 grain RNSP bullets for subsonic 7.62x39 with a 1:10 twist.

It's might be okay to run your load through a suppressor, but it sounds risky to me.

[Hoser]

For 308 subs I like Speer 125 TNTs and Trailboss.

[SSChameleon]

I'll try the lighter bullet with Trailboss. The rounds were just under super sonic, I had one round of the 10 where I heard the crack of the bullet.

[Great-Kazoo]

some helpful info

https://www.hodgdon.com/wp-content/uploads/2016/11/trail-boss-reduced-loads-r_p.pdf


https://forum.snipershide.com/threads/subsonic-308-and-trailboss.6877185/

[Great-Kazoo]

I'm working on 308 subs. I'm running them through an 18 inch 1/10 barrel. I loaded some 168 grain boat tail with Clays using the data from the Hodgdon website.

I loaded 10 test rounds, then shot 7 rounds from 20 yards without a suppressor to check for signs of key holing. Everything looked good, so put the can on and backed up to 100 yards. Three shots keyhole at 100 yards.

I won't make it back to the range until later this week, and plan to try 50 yards and 75 yards without the can. From those who have experience, what I want to know is:

Is it common or expected for subs to tumble inside of 100 yards?
Is it safe to run these through a can?

from my experience, yes and maybe. I did 5.56 subs using 3.2 grs of titegroup. Quietest thing you never heard, when suppressed out of a bolt action, or AR. I did see sporadic keyholing @ 100yds. What i did definitely see was at least a 12" - 18" drop @ 100. if not more.


I'm a little surprised they keyholed actually. Any idea what the velocity is?

You may try moving up the velocity a little or move to a heavier bullet.

I don't have a lot of experience with subsonic .308, but I use 180 grain RNSP bullets for subsonic 7.62x39 with a 1:10 twist.

It's might be okay to run your load through a suppressor, but it sounds risky to me.


I'd set up targets @ 7-25-50 and 100 to see what if any keyholing there is. if it's consistent keyholing under 100 then pass on running a can.

[SSChameleon]

Thank you all for your input.

I had the chance to run some 168gr with trailboss at 20, 50 and 70 yards. No signs of keyhole at 20, by 70 yards the holes in paper were no longer round. So I'm probably done with those.

I couldn't find 125 TNT locally, and online is sold out, so I ran some 150 gr boat tail with 9.5 grains of TB. They were right under 1100 fps and left nice round holes in the paper at 70 yards. I found a box of 150 gr RN I'm going to try next.