Bullet selection for 600yds F class .308

[5RWill]

Well i went and talked to my local gunsmith today who shoots F class and is going to let me shoot his 6mm Dasher. He wants me to get my .308 ready which i will. But he recommended that i ditch the 155gr lapua scenars all together and go with a 168gr SMK for 600yd. So i type in the ballastic calculator thinking that maybe the 168gr is somehow less affected by wind but it isn't. So other than that i can't see where he is coming from. Just doesn't make sense. Maybe Lapua bullets cost a little more but i just don't see a downside to shooting the 155gr scenar. He also said i need to be able to shoot a 1/2 MOA 20 shot group, IDK weather he is just hell bent over how he learned his competition ways or if that is how the BR community is... but God.. I understand he is in large part referring to consistency which is also affected downrange. I show him my latest group of 9 shots of 155gr scenars which was about a .800 hole. I plan on doing a little prep work on my brass and switch to softer charge primers which should help the group shrink and give me more consistent muzzle velocity. Should i do what he says or am i missing something?

[HiBC]

First,I do not shoot competition,and you probably already know more than I do..
No doubt the Palma type 155 bullets can shoot world class,but,in my limited experience,those bullets might prefer a rifle chambered/throated for them.
I experimented with the new 155 Sierra Palma in an AR-10 T that has been generally .5 moa with 168 MK's and Varget.From this rifle,and my DPMS LR 308 L,we got about 2 moa with the new Palma.The older 155 MK shot dime sized ragged hole from the Armalite and a touch over 1 moa from the DPMS.
I read on another forum something about a new PTG reamer tailored for the 155 Palma bullets.I is designed to work with the short bearing surface on these bullets.
As my handle HiBC suggests,I do like sleek efficient bullets,but some frustration/experience has taught me that some of the less efficient forms and heavier bullets are more forgiving in leaving the case neck and entering the bore square and centered.
I guess its about less ogive and more cylindrical bearing diameter.

[Bart B.]

Any good lot of Sierra's 30 caliber match bullets will shoot 3 inches or better at 600 yards......if your barrel's spec'd to handle them and your ammo's made properly. But testing 'em at 100 yards is a waste of time. You have to test at 600 yards to find out. Here's why.

The variables in ballistic coefficient they all have due to their slight imbalance will cause vertical shot stringing. And the spread in muzzle velocity also causes vertical shot stringing. As range increases, so does the effect seen on target. Which means a 3/4ths MOA group at 100 yards won't produce a 3/4ths MOA group at 600 yards. To shoot inside 3 inches at 600 yards (1/2 MOA), you've got to produce 1/4th MOA at 100 yards; at worst, not once in a while.

Sierra Bullets used to package 1000-bullet boxes of super-accurate 30 caliber match bullets at their California plant. These tested at 2/10ths MOA or better in their indoor range, sometimes down to 1/10th MOA. They were sold only at high power rifle matches through one dealer who brought them. Accuracy was 30 to 40 percent better than what could be expected for their regular bullets sold in 100-round green boxes. But they quit doing this when the moved to their current site in Missouri.

Which means that you have to test bullets from several lots to see which ones work best. Your barrel needs a bore diameter of about .2980-.2990" and a groove diameter of .3075-.3078" for best accuracy with their 30 caliber bullets at .3082-.3084" diameter. Twist has to be correct for the bullet, too; 1:13 for 155's, 1:12 for 168 & 175's, 1:11 for 180-190's, 1:10 for 200's, 1: 9 for 220's and 1:8 for 240's. Best accuracy I know of has been done with standard SAAMI minimum dimension chambers with the lead cut to just touch a seated bullet. Fired cases properly full length sized in dies with a neck bushing sized 2 to 3 thousandths smaller than a loaded round's neck diameter seem to produce the most consistant and best results. Top competitors as well as Sierra Bullets have been sizing fired cases this way since the 1950's.

All this plus having your rifle built correctly; bolt face squared with chamber axis, receiver properly expoxy bedded, repeatable light-pull trigger as well as sights that don't shift from shot to shot.

And don't test you loads using a bench rest with the rifle atop bags or some other support; nobody shoots "perfect" shouldering a .308 Win. this way as they have too much recoil. You'll do better shooting prone properly slung up with a good fitting shooting coat and a sand bag under the stock toe and fore end. Shoot at least 20 shots per test group to get statistically significant results; 5 shots' are only about 40-50 percent reliable.

[Old Grump]

Your gun will tell you. My favorite load might make your gun look like a dime store has been, any 155 gr bullet in my gun barely keeps me on target but 180 grain puts me in contention with anybody. Never let anybody tell you their pet load is the must be for your gun. Only time on the range with a variety of brands, weights and styles will tell you which bullet your gun likes.

Good shooting and enjoy, the search is where the fun is.

[5RWill]

The gun is a sturdy gun. It's a 700 5R bedded in a McMillan A-5, topped with a U.S. Optics SN-3. I plan on adding a custom barrel after a while but don't have time for it right now. The twist rate is 11.25, which astoundingly does fairly well with the 155s. I see now he was just referring to accuracy overall. But i still have some 155s left and i'm changing primers to CCI BR2 or Federal Gold match. I've been using magnum primers which i believe has led to a velocity jump and some vertical stringing. If i can "fix" this in a sense i will try to keep the 155s. I'll definitely pick up some 168s or maybe even higher. I know the rifle is acustomed to heavier bullets. One thing i must say is i'm not confident in my ability to hold a 1/2 MOA 20 shot group. Lol hell i'm just getting to where i can have a correct trigger pull and sight picture when the gun goes off and actually shoot Sub MOA groups. I've come a long way since first registering on this forum and having 2 inch groups till now. Still that being said being in college and not having my reloading setup doesn't permit me to shoot every weekend like my gunsmith does. I'll definitely give the 168gr a try though just to see. Here's the rifle and group.

[5RWill]

I'm going to try some 175 SMKs and maybe 190 SMKs just to group them but if i can get the MV consistent on these 155gr i'm keeping em and here is why. Sure these loads i have right now have a good bit of vertical stringing in them because they're inconsistent. I figured i need to get rid of em so i can start over again. So today i shot at 300yds. I looked up the weather and it said 17mph wind gust. So the far ones to the right are my first 4 or 5 shots out of a clean bore with 9/10s mil windage. I have no windmeter lol. So i drove downfield looked at them and backed off 4/10s. So at 5/10s mil windage i shot my last 4 shots. And on the last 3 i must have caught the wind being constant because man for me or to me thats a hell of a 300 yd group. I swear if i can just get a consistent muzzle velocity i think i'm going to have to stick with these little bullets. Sure i still want to try the heavier ones now but my gun even though a fast twist rate loves these things. I'm guessing the reason it stabilizes well in a fast twist rate is due to the length of the bullet. It's a bit of a slender/long bullet for a .30 cal. Anyway here is the group.

[kraigwy]

What do High Power Shooters use at 600 yards?

I think if you check around you'll find the 168 SMK leads the pack.

That's the round the Military chose for their match ammo, (M-852)

Past 600 I'd go to 175s but up to and including 600 I've found the 168 SMKs hard to beat.

[5RWill]

Guess i'll pick up a box of everything load some groups see which is the most accurate and shoot that. Only tiny problem i have with the 168gr is it's performance at 1000yds. I will be shooting F-class 600yds but most of the time i'm going to try and shoot at the range i'm making from 400-1000yds. How are your experiences on the 168gr out to 1000yds kraigwy?

[Clifford L. Hughes]

Dear Blackops 2

I'm not sure what F matches are because my competition was shooting the NRA National Match course or the Marine Corps course in the 1960's. I shot master with both the rifle and the pistol. I competed with both the M-1 and the M14. The 600 yard rifle target was 20 inch black and a ten inch V ring.

Using match ammo we pulled the bullets and replaced them with 180 gr. Sierra Match King for the 30/06 and for the .308 the 168 Sierra Match King. Both shot excellent.

Wind drift is not so mucn a matter of velocity alone as is how fast the bullet slows down while fighting air resistence. That is why the High COE of the 168 and the 180 work so well at long range.

Semper Fi.

Gunny Clifford L. Hughes
USMC Retired

[kraigwy]

How are your experiences on the 168gr out to 1000yds kraigwy?

They don't work for me, they have a tendency to tumble.

If I was going to shoot (and I do) 1000 yards with a 308 I'd go with 175 Grn Sierras.

175s will shoot at 600 also.

[1911rocks]

I use an AR Platform (DPMS LR308B). I use either a Sierra 155gr Palma Matchking or a 168gr Sierra Matchking. Powder is Varget or Benchmark. The interesting side is that the 155gr Palmas are great at 1000yds. They are way more wind sensitive at 1000yds than the 168gr Matchkings. The 168gr Lapua Scenars have a real edge at 1000yds out of my gun. At 600yds they are even steven with the 168gr Sierras. 173gr are just too quirky out of my AR platform, but, they win out of my 10FP. It's all very gun unique. You got to experiment.

[5RWill]

Going to try 175 SMKs or possibly berger 175 BTHP BC of the berger is .515 and the seirra .505. Only downside is the bergers are freaking expensive. In this case i want a multi purpose bullet. Something that will be accurate at all distances, or 600 and on. First thing is first before i buy anything i'm going to switch primers tighten up some brass prepping and see if i can get more consistency out of the 155gr scenars.

[HiBC]

FWIW the GI 7.62 sniper rd uses the 175 MK.

[5RWill]

Going to definitely get some SMKs.

[edward5759]

What ever your gun wants to shoot at 600 yards!
I shoot a lot of F class, A guy I know, "I'll call him Frank".
he shoots a .308 with a 1-12 twist barrel shoots 147 and 150 grain bullets. He has had several wins with this rifle as well. Bob shoots 172 grain Mexican pull downs in a Remington 700 with a Douglass barrel he does great!
I shoot a Remington with a Kreger barrel 1 in 9 twist and I shoot 168 grain bullets.
The thing is "YOU" can't decide for your rifle what it likes. try a lot of combination's of bullets powder ETC. you will find the guys out in the 600 to 1000 yard line quite helpful and ready to help.

Ed 5759

[amamnn]

This is not the forum to be asking that Q-- go to benchrest central and look up the F-class section--also 6mmbr.com is another good place to look around for the info you seek.--
Unless you told your gunsmith you were married to the .308--if he was a real pal he would have told you how easy it is to convert your rifle to the more competitive 6BR family of cartridges--you'll notice he's shooting one in the 6 Dasher...................Lapua is now marketing a 105 gr ScenarL that will be making some waves in F-class and 600 yard BR soon.............

[5RWill]

Thats the thing this rifle isn't a F-class rifle. It's a precision rifle meant for practical long range matches. Making a hit on a steel target at an unknown distance. He asked me to bring my .308 so i figured i would shoot it. I'm going to go to F-Class for more shooting time and the experience. It's not something i'm really wanting to go all out for.

[firewrench044]

The twist in your barrel is perfect for 175's
try 42 to 43 gr IMR 4064 or RE15 with bench rest primers
some barrels prefer one over the other
a go to load for most competetors in this area
( mine likes 42.2 gr 4064 )
( the 175s will hit lower and to the left of the 155s ( its normal ))

[5RWill]

Hell the berger 175 BTs (G1 BC .515) @ 2753 actually performs better than than the 155s (G1 BC .508) @ 2830. Now Thats my highest expected velocity for the 175gr though, i'm not expecting it rather hoping for it. 2650fps will still keep me supersonic to 1000yds. If i could get it @ 2700+ it remains supersonic till 1100 . I wonder why most limitations stated for the .308 is 800m? If the military is using 175gr FMJs i'm guessing with a .50 BC or higher and running 2650 or more it should be effective to 1000yds right? Most factory ammo that tends to shoot so well though such as Black Hills runs around 2500 though. I'm guessing the military rounds are around that also.

Thanks for the load data Firewrench.

[Wildalaska]

try some 185 scenars

WildnicebcAlaska ™©2002-2011

[5RWill]

I looked at some 185s also. The only thing i worry about is velocity out of a 24" barrel with such a heavy bullet. Will try them though. First i'm goin to get a couple of supplies, Pimer ram, CCI BR-2s, another 50 cases of nosler custom brass, some bortech eliminator, and berger 175gr BT match.