1-11 twist .308 sub loads?

[dcnyli]

Any advice on places to start for a 24" .308 1-11 twist barrel for a good subsonic load? I normally send 175gr VLDs @ 2780fps, but this is my first foray into subsonic..

Any and all advice is appreciated

 

[dcnyli]

really?...

 

[cruizer]

Speer 180gr round nose flat base bullets
11.1gr of trail boss works for me. I'd recommend starting at 13-15gr and back your load down until it is subsonic.

 

[dcnyli]

Speer 180gr round nose flat base bullets
11.1gr of trail boss works for me. I'd recommend starting at 13-15gr and back your load down until it is subsonic.

Thank you! Are these the bullets you mentioned? Speer Bullets - Product Details

 

[cruizer]

Yes


Sent from my iPad using Tapatalk

 

[Xtremegunnr]

I have a 1/10 and 1/8 and shoot 175 to 225 grainers.

I find between 10 and 12 of trailboss works great at 2.8 oal.

Good to 400 or so yards but has a crap ton of drop obviously. My 175 is 10.5 grains and shoots 1/2 moa nearly every time out.

Don't put a can on it until you make sure they don't keyhole

 

[D_Lamz]

11.25 twist in a 22in tube.
175smk with 10.4gr trailboss

 

[sigma2chi]

26" barrel, 11.25 twist
This is 10.6 gr of Trail Boss pushing 175 gr Berger OTM.
.308 Suppressed @ 200: .308 Suppressed @ 200 - YouTube

 

[Darkker]

JBM - Calculations - Stability

Look-up the length, and fill in the blanks; will tell you if it is stable.

 

[dcnyli]

JBM - Calculations - Stability

Look-up the length, and fill in the blanks; will tell you if it is stable.

Thank you Darkker, and everyone else who has chimed in on this thread. I was lucky enough to find some TB at an LGS and some Speer 180 grand slams(though I wanted 180 Hot Cors, slim pickin's these days locally)

I get a 1.795 with a speer 180gr grand slam @ 1050fps… my regular loaded 175gr VLD gets 1.80 @ 2780fps (.24moa or better load)

loaded up 3 rds each
13
12.5
12.0
11.7
11.4
11.1
10.8
10.5
10.2

will see how it goes and update after…

 

[No1]

my most stable load from 1:11.25 .308 is
6.0g Bullseye
175g bullet
1050fps

 

[dcnyli]

went to range today for testing… here's some info

180gr Speer Grand Slam, Trail Boss Powder, Winchester LR Mag Primers, .015 Jump, Lapua brass

First i loaded some single shots to be safe and slow down carefully(then 3 rounds of the lower weights each)

13 1277fps
12.5 1235
12.0 1202
11.7 1164
11.4 1172

11.1 1114 this shot a nice tight group, but i kept driving down the charges
11.1 1131
11.1 1117

10.8 1065 this opened up a bit, also possibly the beginning of key holes*see pic*
10.8 1092
10.8 1082

10.5 1068 still around same size as 10.8 group but also maybe keys
10.5 1059
10.5 1059

10.2 1044 a tiny bit tighter and i think keys, stopped here
10.2 1032
10.2 1027

When i looked at the target, the "black" around the bullet holes wasn't round after a point *see pics) so I assume this is key holes… I'm going to try out some Sierra 180GR round nose this week also… Also afterward I shot some of my regular loads to be sure I wasn't just shooting poorly… I wasn't , this subsonic thing is a nice puzzle

 

[dcnyli]

round 3 this weekend, with drilled out primer holes on the brass and charges within .1gr & the fps is ideal… At this point just trying to see if I can get the TB to burn better or just leave less crap on the end of the barrel

This is after 30rds were fired… needed carbon solvent to get off and killed POI consistently immediately after with regular ammo…. *note, rifle headed to smith for threading the crown & brake mount install shortly… just working out load dev in advance.*