.308 Quickload Data

[The Cupcake Kid]

If you want to do well at 1000yds with a 24" barrel, the best way forward, IMO, is to investigate the slightly heavier bullets like the 175 mentioned above.

You'll still struggle to get high enough velocities to keep them well into supersonic at 1000 in all conditions, so you might want to look at the Berger Tactical range, particularly the 175gn Tactical OTM. These bullets are designed to remain very stable in the transition from supersonic to subsonic (transonic) and in my testing, they work very well. I shot out a Rem 700 barrel finding this out, so save yourself the money and just go straight to the 175gn TOTM!

I shot these up to 1200yds from a 24" 1:12 Rem. and the accuracy was as good as it gets for a standard factory barrel.

[ovenpaa]

Nope, I have to disagree when it comes to the 175s. The right 155 will comfortably get to 1000 yards with a 24" barrel and be reasonably accurate, certainly 1 MOA and better. 1200 yards with the same rifle can be problematical unless it is a warm day.

The one I did see a lot of good things with was the Lapua 170LB

[The Cupcake Kid]

I didn't say the 155s couldn't do it. It's just that you're up against it with a 24" barrel and the limited case capacity of the .308, particularly in difficult conditions, with a standard rifle/barrel.

I also tend to go along with the idea that you need to keep the bullet at Mach 1.2 at the target and not just above the speed of sound. That's tough with any bullet weight and the .308 cartridge at 1000yds+, so the next best thing is to choose a bullet which stays stable in the transonic zone. Hence my recommendation of the TOTM.

It's only my personal view though, of course. Best way always is to try all the things different people say and find out what works best for you and your rifle.

[StanDeasy]

I don't care what QL says, I don't believe you will get accurate results at 1000x from the 2155 SMK out of a 24" barrel. Why do you think TR shooters use 30" barrels with this bullet?

I would go for the 190gr SMK, which will still be supersonic at 1000x when launched at MVs which are achievable in the 308 at safe pressures with propellants such as N150.

Running the numbers thru Brian Litz's ballistics solver bears this out:

Bullet G7 BC MV 1000x Vel
190 SMK .268 2550 1160
155 SMK .214 2850 1077

Plus the 190 SMK is known to be more stable than most in the trans-sonic region.

SD

[ovenpaa]

My Accuracy International has a 24" Border barrel with Moly coated Lapua 155 Scenars, Lapua brass, OAL of 2.890" and N540 in front of Fed210M primers.

I shot next to Rox of this forum at 1000 yards, he was shooting a TR rifle and I was shooting my Accuracy International and I would like to think there was not a huge difference between the two of us on the day. Other than that I have only shot next to TR shooters at 300 & 600 yards.

[StanDeasy]

If you had been shooting the SMK 155 (2155) there would have been a huge difference.

[EagerNoSkill]

Please could I ask if someone is kind enough to run the following through Quickload?
I've developed an accurate load but I've been restricted to shooting it on Short Siberia to date and I just wanted to theoretically check pressure and velocity to see if it's got the legs to go out to 1000 yards.
N140 - 41.2 grns / SMK 155 (2155) / CCI 200 primer / Seated 40 thou off the lands / 24" Barrel - 1:12 twist
Thanks very much in advance.
Adam

Hi All

No need for handbags at 10 paces! Helping a fellow forum member out with some info.
I used same 308 Win generic profile for the 190 SMK and 155 SMK

ENVIRONMENTAL FACTORS
Firing Point speed of sound 1090.72 fps / Pressure 29.53 / Temp 32 F

The Sierra 190 SMK are a fine alternative
Using Vit N150 it shows 2,557 fps at 60,186 PSI
Sierra Bullets Infinity shows it retaining velocity of 1197 at 1000 yards
Time of Flight 1.7538 seconds
Drops are : 40.5 moa and 10 mph drift is 9.8 moa
Minimum barrel twist rate is 1:12
Sierra says G1 BC is about 0.533 (Brian Litz)

The Sierra 155 SMK as close to this morning has (I equalised pressure kind of)
Using IMR 4895 it shows 2,926 fps at 60,081 PSI
Sierra Bullets Infinity shows it retaining velocity of 1,177 at 1000 yards
Time of Flight 1.6342 seconds
Drops are : 34.1 moa and 10 mph drift is 10.4
Minimum barrel twist rate is 1:17
Average BC is about 0.417 (Brian Litz)

Swings and roundabouts - 190 less windage more elevation.

So my point... well
1. I never said it was the optimal combination - I just tried to help him get what he had onto paper
2. Yes there are many better likely combinations - that was NOT the question posed!
3. If all he had was 155 SMK at least he could get onto paper - he is still well into the transonic zone at 1000 yards and his scope could probably have the range.
4. With 190 gn he needed 7 moa more scope elevation to hit the target - less likely with the scope most users have.

The 2156 is a much better bullet than the 2155... as are Scenars.

[EagerNoSkill]

So what does 2,850 with a SMK 155 that StanDeasy quotes get achieve:

LITZ SOLVER
Bullet G7 BC MV 1000x Vel
190 SMK .268 2550 1160
155 SMK .214 2850 1077

SIERRA
190 SMK .268 2558 1197 (+37 fps on Litz)
155 SMK .214 2850 1137 (+60 fps on Litz)

Set at 2,850 fps .. Sierra Bullets Infinity shows it retaining velocity of 1,137.7 at 1000 yards
Time of Flight 1.6960 seconds with Drops of 36.4 moa and 10 mph drift is 10.8 moa
so - 80 fps at barrel requires + 2.3 moa more in elevation and 0.4 in windage!

The key point of long distance shooting is that even the smallest change at the outset has increased / magnified impact at 1000 yards.
There are so many factors and nuances that can influence results dramatically. We helping a fellow shooter get on paper and have some "Recoil Therapy"
:cheers:

[EagerNoSkill]

I don't care what QL says, I don't believe you will get accurate results at 1000x from the 2155 SMK out of a 24" barrel. Why do you think TR shooters use 30" barrels with this bullet?
SD

"I don't believe you will get accurate results at 1000x from the 2155 SMK out of a 24" barrel."
You don't have to believe it - enough people have shot accurately enough at 1000 yards with the 155 SMK.
Defining the level of required accuracy is more important.

It is NOT magic - if the bullet is launched at the velocity of 2950 the bullet doesn't care!
If several SMK's are launched at 2,950 at the barrel - be it 24, 26, 28, 30 or 32 inches its inherent accuracy is determined by:
1. The quality of the bullets - bullet by bullet
I have measured the bearing surface of 155 SMK 2156 and found variation off +- 35 thou and this alone will cause much distortion.
2. Damage and distortion of bullets as it travels down barrel - quality of bore / crown
3. The quality of the crown and the destabilisation at the muzzle by gasses

Why do TR rifle shooters use 30 inch barrels.
1. Longer barrels equal longer sight picture - enhancing their ability to aim fine through the iron sights they have.
2. They generally use ISSUED ammo - they cant fine tune loads - they use longer barrels to maximise velocity.
3. Their rules allow it

TR shooters are ridiculously accurately !!
Having shoot with Steve E and Rox from this Forum I am gob smakked how accurate they are.
I have not had chance to be embarrassed by GazMorris yet !

[EagerNoSkill]

Last point .... In October 2011 I lay on 1000 yards at Stickledown and I was shooting Ovenpaa's AI (was .308 now its more like .311 ). on a Harris bi-pod

A 24 inch barrel - stock trigger and in a fair breeze I was keeping the bullets well in the 4 circle of a F-Class Target
- about 20% 3's ( i was a newbie!)
- about 40% 4's
- about 30% 5's
- about 10% V's (just enough to Hook and Delude me)

Anyway my point you may ask...... well the AMMO was Danish Machine Gun ammo
- military spec surplus machine gun ammo - designed to disperse holding a F-class 4 circle!
That is not supposed to be possible either

More often than not the PLATFORM ie the firearm, scope etc and the AMMO far exceed the capabilities of the Baboon trying to drive it! :lol: