Sub-sonic accuracy

[Lightload]

Loaded up some sub-sonic 308 loads yesterday. I found that 9.7grs of Trailboss behind a 168gr. HPBT would give me 1054fps. Just about right I'm thinkin'. But....they print two inches at 50yds.

I'm going to try some 178A-Max and 175HPBT's today but I"m not sure if they'll do any better out of my 10 twist barrel. I'm thinkin' maybe a short fat 180gr. round nose might do better in that barrel.

Anyone have any experience with this kind of stuff?

 

[Ohio Varmint Shooter]

Not trying to stir up trouble....This is a real question:

Why are you trying to make sub sonic 308 loads? What's the purpose? And how far could you shoot such a bullet?

 

[ebb]

No experience at all but have been thinking and researching the same thing. Have almost given up the full length 308 idea. But looking at small case 30 caliber chambering's with .473 base. 30 caliber 7 or 8 twist barrels may be necessary.

 

[matthias]

try some lighter bullets like the 110 vmax or sierra 110 varmint . i would be willing to bet they do better out of the 1-10 barrel sub sonic . at least that has been my experience. then i built a blackout/whisper and have not looked back. good luck

 

[XTR]

Loaded up some sub-sonic 308 loads yesterday. I found that 9.7grs of Trailboss behind a 168gr. HPBT would give me 1054fps. Just about right I'm thinkin'. But....they print two inches at 50yds.

I'm going to try some 178A-Max and 175HPBT's today but I"m not sure if they'll do any better out of my 10 twist barrel. I'm thinkin' maybe a short fat 180gr. round nose might do better in that barrel.

Anyone have any experience with this kind of stuff?

Check stability, may not be stabilizing bullets that long with the tiwst rate and velocity

 

[Taildrag15X]

Not trying to stir up trouble....This is a real question:

Why are you trying to make sub sonic 308 loads? What's the purpose? And how far could you shoot such a bullet?

My brother's suppressed 1-10" .308 Win. likes 155gr. (#2155) Sierra's to break clays out to 400 yds., I don't know the load, LC brass, CCI primers as I did the prep work.

 

[Tozguy]

try some lighter bullets like the 110 vmax or sierra 110 varmint . i would be willing to bet they do better out of the 1-10 barrel sub sonic . at least that has been my experience. then i built a blackout/whisper and have not looked back. good luck

The Sierra 110 HP varmint bullet would be worth trying to get best accuracy at subsonic speeds with a 10 twist.

 

[jbpmidas]

Mine does well with 190SMK and. 10.0 Trailboss.

 

[spencerhenry]

i have a 300bo. it is VERY picky about loads for subsonic. charge weight, seating depth, and particularly brass.

accuracy ranged from 6" at 100 yards, to the best at sub moa. biggest factor was the lot of brass i was using. i was using 220 sierra hpbt matchkings.

 

[matthias]

i have a 300bo. it is VERY picky about loads for subsonic. charge weight, seating depth, and particularly brass.

accuracy ranged from 6" at 100 yards, to the best at sub moa. biggest factor was the lot of brass i was using. i was using 220 sierra hpbt matchkings.

What platform barrel twist etc? The bolt actions I have built have been very consistent most averaging around 1.5 at 100 with one really special one averaging just below .75 "

 

[Lightload]

Ohio Varmint....why subsonic??? In no particular order.

1, It's a fun project to play around with.
2. Shooting in the backyard doesn't disturb the neighbors.
3. The grandkids can shoot the "big" gun without being traumatized by recoil/muzzle blast.
4. And most importantly....I can poach the King's deer on the King's land and the King's Gamekeeper will never hear the shot!

Taildrag....I'm already using LC Match brass and CCI primers so I may as well try your 155's as well!

Matthias....The barrel is a Barlien 10 twist 5R. 26 inches. Rem 700.

So I tried the Horn. 178 Amax's and Sierra 175 HPBT MK's I had to go to 10.4grs of Trailboss to get up to 1080fps. Must be the longer bearing surface but it definitely took more powder to get the Amax's going than the other bullets I tried. After getting the powder right I went to the range and the Amax's did an inch and a half at 50yds.

The 175 MK's got up to speed with the same load I used for the 168's, 9.7grs. of Trailboss. At the range, they did a half inch at 50 yds. Minute of angle isn't bad for the distances I'll be shooting but of course I'll be playing around with some other combos to see if I can do better.

Thanks a lot for the comments!

 

[357Mag]

LL -

Howdy !


IMR4759 has been famous for its utility, in the assembly of " reduced " ( rifle ) loads.
I wanted to find a powder that would produce the best accuracy in my Marlin M-336 XLR .35 Rem
( loads not used for hunting ). I had much better success shooting 4759 in my Marlin, than I did with any other powder.

While I was able to obtain a good group now & again when shooting Trailboss, those were noteably under-powered loads.... and were highly susceptable to wind. Good accuracy that I was able to attain, I was unable to repeatedly produce. I was not able to get enough Trailboss into the case,
14.5gr being the max; under those hyper-accurate Rem 150 PSPs.

With IMR4759 & the 150s, I was able to obtain a .200" 3-shot sub-group @ 100yd; and an over-all 5 shot group of 5/8". And, that was after I over-corrected for windage; and put the last 2-shots
wide.

With regards,
357Mag

 

[1066]

I can see the appeal. I would think that right in cast bullet territory, take a serious look at the Cast Boolits web site, I'm sure there's information there that will help.

 

[Sniper338]

I havent gotten around to it yet but im going to do 208 amax bullets with trailboss in my 10 twist 308. I know a few people that shoot the 208amax subsonic in their rifles... its supposeto be good from what i hear!

 

[d.id]

I have a 16" 1in8 twist.
Horrible with light bullets, great with 208 a-max at the lands but did not like jump at all.
Best load was with 225 h-match bthp over 12 grains of trail boss.