rammac
Well-Known Member
1 in 12" twist?
Max effective range of 168 Eld M in 308?
- Thread starter Stovetop535
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rammac
Well-Known Member
Buy a copy of Bryan Litz' book "Ballistic Performance Of Rifle Bullets".
You'll probably find that the 168gr ELD-M isn't well suited to your rifle.
You'll probably find that the 168gr ELD-M isn't well suited to your rifle.
Whats your twist rate?
If you guys want a long range 308 with the 168-175 class bullets you can get thru transonic transition with a faster than normal twist rate 1-8 or 1-9. i would use the 1-8 for short barrels and the 1-9 in long barrels. I say that because I have shot out to 1 mile with accuracy when you overspin that class of bullet. I shot this at a mile with 168 berger hybrids. If you look over the bottle cap in the first pic you can see some grain bins, that was the shooting location. If you go to 6mm benchrest/accurate shooter daily bulletin and search Jim See there is a full article on it.
If you guys want a long range 308 with the 168-175 class bullets you can get thru transonic transition with a faster than normal twist rate 1-8 or 1-9. i would use the 1-8 for short barrels and the 1-9 in long barrels. I say that because I have shot out to 1 mile with accuracy when you overspin that class of bullet. I shot this at a mile with 168 berger hybrids. If you look over the bottle cap in the first pic you can see some grain bins, that was the shooting location. If you go to 6mm benchrest/accurate shooter daily bulletin and search Jim See there is a full article on it.
Attachments
My 168 run at 2456 FPS at muzzle
At 1000 yds 1052 FPS today DA is -655 ft temp is 46.4 f
At 1000 yds 1052 FPS today DA is -655 ft temp is 46.4 f
Stovetop535
Member
Twist is 1-12.
Ill check out that book as well, thanks.
Maybe ill try some lighter bullets and see how they shoot.
Ill check out that book as well, thanks.
Maybe ill try some lighter bullets and see how they shoot.
berger makes some 155 that might work well with the 12 twist what Jim is saying makes sense nice to learn something thank you
Possum Cop
Well-Known Member
I see OP responded. I'll look at the book. My rifles have 1:10 and 1:9 in the 20" shortys. I use my short barrels to shoot pigs from point blank to 400 yards.
rammac
Well-Known Member
You're going to have to drop to a 150 to 155 grain bullet to get better performance in that barrel.
According to Litz' book, your bullet (168gr Hornady ELD-M) is not stable under the worst case conditions, which are pretty close to your description of altitude and temp. You would need a 1 in 11" or 10" twist to stabilize that bullet under your conditions. A Hornady 150gr FMJ-BT would probably work.
redneckdan
Well-Known Member
When I have had similar experiences with a .223 load its was due to going trans sonic. There is buffeting that occurs as the bullet approaches the sound barrier. I'd think 1500fps would be high enough, 1300 I start to wonder.
My practice .223 load goes trans sonic between 550 and 650 depending on density altitude. I have had days where I can consistently hit the 8" @ 500 yds and cant touch the 16" @ 600.
My practice .223 load goes trans sonic between 550 and 650 depending on density altitude. I have had days where I can consistently hit the 8" @ 500 yds and cant touch the 16" @ 600.
Stovetop535
Member
Thanks for the input everyone. I will pick up some lighter bullets and go from there.
Its good to know the limitations of this round for this gun as we use it as a duty round for our precision rifles.
Its good to know the limitations of this round for this gun as we use it as a duty round for our precision rifles.
Possum Cop
Well-Known Member
I used the 155 grain Palma bullet in a 1:10 twist with good results.
spinlite
Active Member
Does anyone know if these will still expand at speeds as low as 1500 fps?
