1/10..168 or 1/12...155?

[Texas Solo]

I'm a little perplexed by the bullet weight/twist/velocity thing. I'm considering a #12VLP or a F/TR in .308.
The VLP is a 1/10 twist, the F/TR is 1/12.
The 1/12 would require lighter 155gr bullets, whereas the 1/10 would be better of with the 168/175gr.
I can go either way with that, but I don't understand what advantage the heavier bullet seems to have at greater distances (1000yds.)
Logic says that the 155 will be easier to keep super sonic and have less drop, but the heavier bullets seem to be what most folks are using.

Can someone please explain to me what advantage, and in what situation, the heavier bullets have over the lighter ones?
I know I'm missing something here.

[rjtfroggy]

Run with the 1:10 then you can use either the 150,155 or the 168,175. With the 1:10 you can try them all and see what works best for you

[stomp442]

The advantage of the heavier bullet is a higher b.c. which helps buck the wind and deliver more energy at long range. I too say go with the 10 twist and you can shoot just about any bullet weight you want. With the 12 twist you limit yourself to that bullet weight.

[You-Two]

Texas Solo,

My Savage F-T/R (.308) shoots the 175 Nosler and SMKs just fine with the 1/12 twist. About 2750 with 43gr Varget. Not sure about anything heavier though.

[scope eye]

My 26 inch Shilen 12 twist shoots anything from 90gr thru 180gr all with excellent groupings.

Tanks Dean

[darkker]

The Berger VLD's are little different animal, But if the slow twist(12) scares you, consider this:
I will probably have this backwards, but the info is correct.
The Army shoots 175 SMK's with a 10 twist. The Marines shoot the SAME ammo with a 12 twist.
One "limits" the max effective range to 900 meters, the other at 1,000.
Both have confirmed kills at greater distances than either.

The "staying supersonic" issue is a question of stability through the trans-sonic range; because of the tail angle. Relative to Sierra, Bergers tend to not survive nearly as well. They have a lower BC, but don't have as good a survival rate.
YMMV

[acemisser]

for what it worth if anything....I have the Rem 700 SPS rifle with the 20 inch barrel
and the 1 in 10 twist...I have tried lots of loads and bullets...
I get my best groups with 175 gr.SMK and with reloader 15 powder..This load will group
in 1 1/4 at 250 yards...Everyone says the lighter bullets will work,but you can't prove
it to me...Varget was the worst ...But maybe I just did not plat with the loads enough
and each rifle is different as well as what some people consider good groups...
Imean I could tell you I had good results with x bullet and x powder and only hitting
a 8 inch paper plate at 100 yards..See what i'm saying?

[Luckus]

My 12 FTR was very accurate (2's and 3's) at 100 with 175 SMK's. It was the only bullet I used at 300, 600, and 1 K. I never tried anything heavier. Luckus

[Grit #1]

My F-class heavy gun is a 12 twist I run 48.5 grains of 4895R 190SMK for 2650fps shoots 1000 yds and wins matches.
Best regards,
Grit

[rrflyer]

The 1/10 or 1/12 will shoot the 155 -208's just fine.


The only problem with transonic performance had to do with the 168gn Sierra match and even that Is under specific circumstances.

The 155 lapua is an awesome bullet but needs to be pushed above 2900fps to really shine.

The 175smks and 178amax just work.

[acemisser]

so why is the 155 lapua such a great bullet? Never tried any befor.I have heard
others say the same thing as you..Maybe I should get some and try them....?

[scope eye]

Isn't anything Lapua makes great, I personally love there 30 cal 100gr HP.

Dean

[darkker]

1) The only problem with transonic performance had to do with the 168gn Sierra match and even that Is under specific circumstances.

2) The 155 lapua is an awesome bullet but needs to be pushed above 2900fps to really shine.

3) The 175smks and 178amax just work.


1) No actually it wasn't under specific anything, except trans-sonic velocity. Because of the 13 degree tail angle, and a particular ogive shape(moving the CG); dynamic instability is certain at the Trans-sonic range. This has long been well known, and referenced many times.
Here: http://riflemansjournal.blogspot.com/2010/04/history-us-national-match-ammunition.html
You can read reference to very early attempts to use the 168 for sniping(just after M852 became nat. match ammo), but tumbling killed that notion.

2) For a light weight Palma type bullet, the 155 Scenar does have the highest BC. That bullet doesn't need to be pushed above any velocity, it is what it is. 7.2 degree tail.

3) Robert L. McCoy's work shows the best compromise for high BC, and Trans-sonic survivability; is about an 8.5 degree tail. That said the 175 SMK and the 200gr Amax would be great candidates. The 175 SMK and 178Amax, don't have much except for weight, in common with each other.

[rrflyer]

so why is the 155 lapua such a great bullet? Never tried any befor.I have heard
others say the same thing as you..Maybe I should get some and try them....?

Because if you can push it fast enough you can come closer to 260 ballistics with your 308.

[acemisser]

Because if you can push it fast enough you can come closer to 260 ballistics with your 308.

some say push it fast some say you do not need to..Whom am I suppose to beleive? Some say 12 twist some say 10 twist again who do you want to beleive..As far as what some claim to be accurate as accurate as what..to hit a pie plate at 100 yards or to hit a dime at 100 yards...I guess I will have to get some and see for myself..