Thread: 308 Subsonic

Just thinking about working up a subsonic load for my Howa.......

Have of any of you guys tried a 208Amax and trail boss?

Not wanting to reinvent the wheel, so any load suggestions would be appreciated.

Cheers

Ps for hunting reds at about 50-100m

Have a look around the forum, I'm sure there is a recipe somewhere

Thanks, have done a search but didn't find much using a 208Amax

Do you have a chrony ?


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6.5grns works with cast 150grn........

ive been trying trailboss and 150 g cast, 8.5 grains gives 970 fps but only 2inch groups at 50 metres. Still trying but waiting for calm days

Excuse my lack of understanding, but why use cast bullets?

Hate to tell ya but the amax's and SMK s will have difficulty expanding at the subsonic speeds. Amax do most their damage being frangible and at higher speeds and will hit the expansion / frangibility wall pretty quick developing sub-sonic rounds.
I've never had great results on game with the 208s hornady package up for the whisper.

My go in the 300 Blk (same pill different parent cartridge) has been something with a wide impact area Meplat. Best was the Le high max expansions followed by the Barnes tac-TTSX but if you want a good easy to get round try the noslers ballistic tip or even Tnt's.

Just my 2c.

Originally Posted by HOWA308

Excuse my lack of understanding, but why use cast bullets?

To try and get expansion.

Just start with plenty of trail boss so that you are super sonic.
Then work backward 1 or 2 grains less each load until it goes quiet and you have it.
Work back up in 0.5 grins lots to see where it goes supersonic again just to double check and stay well back from that point.

Don't start low and work up or you might leave a projectile in the barrel !!!!!

Originally Posted by HOWA308

Excuse my lack of understanding, but why use cast bullets?

Cheap and work well at sub sonic speeds.

In my experience no normal hunting .308 bullet will expand at sub sonic speeds. They usually just punch a hole, if that is through the brain or spine the result is the same anyway.

Also you might find long pointy bullets don't stabilise out of a slow twist .308 barrel. This means any heavy long range low drag projectiles. Not sure what the limit for 208 gain A max projectiles is but less than 1:10 might be too slow and worse at sub sonic velocities. That's why 300AAC generally has a 1:8 or 1:7 twist barrel.

http://www.bergerbullets.com/twist-rate-calculator/

Doesn't look very stable even from 1:10 twist.

Bullet Parameters
BC0.648 G1
Caliber 0.308
Weight 208 grains
Length 1.533
Gun and Atmospheric Parameters
Muzzle Vel 900
Barrel Twist10 inches
Temperature 20
Your bullet is MARGINALLY STABLE.
Your bullet stability is marginal. You may shoot good groups under these conditions, but the BC of the bullet will not be optimized.

SG = 1.10
Bullet BC (G1):0.648
Adjusted BC for 1 in 10" Twist:0.570
Your BC is being compromised by:12%
Minimum Twist Recommended:1 in 8.50"

found at least one character online who claimed to get 1moa at 100yds using the 208 amax in a 1-10 using trailboss, others got good stability but crap groups . . give it a go you might be lucky

i put away a box of 208s & some trailboss awhile ago with the intention of seeing how far i could target shoot with them, the BC is a lot better than the 197grn flatpoint cast bullets i use . . be interested on how you get on.

have tried 212grn cast using 1-10 twist with good accuracy out to 300yds, slight tippping of the bullet ( oval holes ) so borderline stability with that weight/length of projectile, 1.5moa groups

if your going to go hunting with subs would suggest as others have said go with a BIG flatpoint, for best results go for a front on shot and try to take the pump out, bullet placement is everything. my 2c

good luck .. . R

http://www.nzhuntingandshooting.co.n...t-shots-32366/

Originally Posted by rossi.45

found at least one character online who claimed to get 1moa at 100yds using the 208 amax in a 1-10 using trailboss, others got good stability but crap groups . . give it a go you might be lucky

i put away a box of 208s & some trailboss awhile ago with the intention of seeing how far i could target shoot with them, the BC is a lot better than the 197grn flatpoint cast bullets i use . . be interested on how you get on.

have tried 212grn cast using 1-10 twist with good accuracy out to 300yds, slight tippping of the bullet ( oval holes ) so borderline stability with that weight/length of projectile, 1.5moa groups

if your going to go hunting with subs would suggest as others have said go with a BIG flatpoint, for best results go for a front on shot and try to take the pump out, bullet placement is everything. my 2c

good luck .. . R

A little instability can be a good thing as energy transfer is improved if the bullet tumbles, ive found that unless it hits bone even pure lead hardly expands, so i hollow point a lot of my cast pills for hunting now.( 3030 180 gr rn )