should I move to a 175 - 178 grain for my 308Win Savage?

dfraser

dfraser

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Hi all,

I currently shoot a savage fcp-k in 308win

I am currently using 167 grain OTM Scenars

Talking with a few guys at the range mentioned that I should actually be use 178grain because of my rifle,

167 grain to 175-178 grain really makes that much of a difference for my savage? (24"barrel with 1:10 twist)

My goal the is to be viable out to 600yards to 800 yards, nowhere near there right now, but slowly getting there.

Regards
 
I have the same gun. Past 600 yards you'll be best served by pushing a 155 really fast or going to a 175/178.
 
175 / 178 definitely past 600 ( tends to be the general consensus too) and in my experience this works much better than a 155 travelling fast but YMMV.
 
Yes,

With that twist I would definately try.

The tried and true Varget/175 SMK/CCI BR2 combination has worked very well with many different setups.
 
I have the fcp-sr which has a 1:10 twist rate. I run 175 grain nosler custom competition over imr 4895 and I also run hornady 178 amax over imr 4064. Both are extremely accurate in my gun. I had good results with 168 grainers but once the box was gone, I moved on to heavier bullets.
 
I would have to agree with you. The 178 with that twist of barrel will be a great combination. Just what I have found is that the accuracy could be out at 100 M so you might have to test 200-300 M or yards. I have found that heavier bullets give more consistency at longer range when testing.
 
Out of a 24" 5r tube I push 175's to 2800 fps and 185's to 2700 fps. 178's are somewhere in between. Not all bullets are the same, even in the same weight. I've had good results with Bergers in 175 and 185. The A-Max 178 wasn't as accurate for me, Sierras 175's were very close to the Bergers. I've always had good results with heavier bullets, even out of 1:12" and 1:11.25" barrels. At those speeds ballistic tables are pretty much the same for all those bullets. At 300 meters the Bergers are slightly better for me. We'll have to see what's best to 600 and 1000 meters by giving them all a try when I get the chance.
 
Just out of curiosity, I ran some numbers through the Sierra ballistics program.
These numbers are for 1000m. Bullet, velocity, drop, and 10mph wind deflection
175SMK, 2800, 37.6 minutes, 9.3 minutes.
155Scenar, 2950(observed from my TR), 32.6 minutes, 8.2 minutes.
In comparison, from my .260:
139Scenar, 2950 (observed from my PR), 28.8 minutes, 6.3 minutes.
Both my rifles have long barrels.

Perhaps this is why Andy suggested a 155 pushed real fast.
 
The only thing about the 175 is that you have to get your velocity high for it to work properly for you. Without the velocity you could get worst results or same results as your 168 grains. You will have to get near the max velocity that your reloading book is giving you for the 175 grains to make a difference. I would suggest running ballistic programs with the 175 grain bullets at varying velocity and the 168 grains at what you know and compare.
 
I just started shooting that grain of bullet and i am using W760 powder and I think that I am getting good results. 2650 fps with the same 175 grain Nosler custom competition bullet. Good bullet. I like it over the sierra Matchking. I haven't tried the TMK from sierra yet I am kinda interested in seeing there results.
 
According to the Sierra ballistics program, a 175SMK would have to be launched at 3000fps to match the 1000m performance of the 155Scenar at 2950.
Don't know that 3000fps with a 175 is achievable in a .308.
 
Im going to say no. I have not found a ballistic program that is accurate out to 1000M yet. Im one of those ones that if I can I will put it to the test and sees what happens and hope the programs are in the ball park
 
I have found that the predictions from the Sierra program are very close to my observations and recorded elevations for the 155 .308 Scenar, and the 139 .264 Scenar.
Last time I shot the .260 at 1000m, my elevation was very close to the prediction. Of course, long range elevations will vary, depending on conditions.
For known distance shooting, either on a range or with accurately lasered targets, windage is more important that elevations.
 
Litz published BC for the 175gr TMK

G1 : .522 G7: .267

Length 1.384"


More Litz data:



Lapua Scenar 155gr G7 BC = 0.236
 
155's are a great 308 bullet, TR shooters sure seem to make them work just fine to 1000yard, a few still use them for F-class as well.
I shoot mainly 175gr Scenar L's for F-class and they can do quite well but I push them pretty hard/fast, my best score this year so far was 50-8 at 500m(1/2moa V), though most shoot 185 berger.

I'll take 155gr scenars any day over anything in the 167-168gr range from any brand. If a 308 won't group 155's with 46gr of N150 or Varget, it probably won't group much of anything, or maybe its the shooter...
 
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