155gr 308 out of a 20'' barrel w/1:10 twist?

S

Sikko15

Sikko
Full Member
Minuteman
Jul 1, 2014
18
0
Idaho
#1
Hello All,

I have a 20'' 308 w/1:10 twist, I was told when I bought the rifle that 155gr ammo will not work well with 1:10 twist. Well since I had two cases of ammo bought (long story) prior to receiving the rifle I decided to put the 155's to the test, I have put 60 rounds down range and my average 5 shot groups are between 1/2 and 3/4 moa (with two groups smaller than 1/2 moa). So is there anyone else shooting 155's out of a 20" 1:10 twist with similar accuracy? Oh and I am using factory Hornady TAP ammo.
Thank You in advance for your responses.
 
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#6
Have you guys played with any other powders for 155grain and short 16-18" barrels? I'm about to dive in and am looking at IMR4895. Obviously powder selection to get my fps will be a big help. But the 155's seem the best way to go as well like the OP was questioning.
 
#8
Dyers 155gr over 46.5gr AR2208 (varget) jammed 10thou from a 24" 1:10 Krieger.
46.5.jpg
WP_20130120_010.jpg
 
#9
I have a 22" 1-10 Spencer barrel that loves the sierra 155 gr palma match. I run 44.5 gr. of varget and Federal 210m primers. It drills the same hole every time and kills amazingly well also. I'm re-barreling that rifle with an 18" and will work up the load when that gets done for a dedicated hunting rifle.
I'll also work up a load for the 155's with my Tac Ops which also has a 1-10 but a Krieger barrel.
 
#10
Sikko15 said:
I have a 20'' 308 w/1:10 twist, I was told when I bought the rifle that 155gr ammo will not work well with 1:10 twist.
Click to expand...

Gotta love gunshop employee "expertise". Whoever told you that is an idiot. But then sounds like you figured that out on your own.

I don't have a shorty (mine is a 24" Howa) but 155s at 2900 are my go to load. Using Nosler CCs as of now.
 
#15
Why wouldn't you test something else? If there is a load with less wind drift, wouldn't you want it? Or so you only care about shooting 100 yards?


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#19
If u can get 155 smk old Palma or ncc to 2850 then they will do better then 175@2650. Use the new palma smk(2156) or berger 155 , or any 155 with .500+ bc at 2850+, and they destroy175-178s. My problem with 18-20" 308 is that the ones that i had could only muster up 2750ish with accuracy. I ended up using 175s in those. I would suggest powder in the h4895 burn rate, or a hair faster, to get a little more speed in the short barrels. I tried it and 8208(temp sensitive) and still could not find an accurate load above 2750ish. But these loads were in a 18.5" ar10 and a slow poke remington barrel that shotgunned any load over2700fps.
 
#21
I have a 20" 10 twist shooting 155's 1/2 moa and under. Tell that gun store guy he needs to do more shooting and less talking.
 
#23
How many of you guys have competed with 155s? I gave my friend a box after I found I couldn't get the speed to beat 175s. He ran them for an F-class match and the wind spanked him. Remember use is more important than anything. If 100 yard groups get your jolly, hell, who cares. 100 yard groups mean nothing to most guys. I'd shoot .223 if that was all I was doing anyway.


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#24
T2CH said:
I have a 22" 1-10 Spencer barrel that loves the sierra 155 gr palma match. I run 44.5 gr. of varget and Federal 210m primers. It drills the same hole every time and kills amazingly well also. I'm re-barreling that rifle with an 18" and will work up the load when that gets done for a dedicated hunting rifle.
I'll also work up a load for the 155's with my Tac Ops which also has a 1-10 but a Krieger barrel.
Click to expand...

So if your going for the distance shot, which do bullet do you go for with a short barrel?
 
#25
Not sure what comps have to do with anything Tyler. I can run a 175smk@2700 vs. a 155(2156 .504bc)@2890 on shooter or jbm and see that the 155 is .2 mils better in the wind and almost 2.0 mils flatter at 1k. That much better trajectory puts it over the 175 at ukd targets
 
#26
6brshooter said:
Not sure what comps have to do with anything Tyler. I can run a 175smk@2700 vs. a 155(2156 .504bc)@2890 on shooter or jbm and see that the 155 is .2 mils better in the wind and almost 2.0 mils flatter at 1k. That much better trajectory puts it over the 175 at ukd targets
Click to expand...

Comps have to do with if you're giving something up or not by shooting 155s. It's application of the load vs shooting groups at 100 yards which is what it seems some here are most concerned with.

I could never get close to 2890 with a 20" gun. Also, have you verified those numbers? In my experience some of the 155s aren't as high a BC as advertised.




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#27
Never competed with a 20", most guys i know run 24"+. I can get that in a 24", my earlier post said i couldn't get much over2750 in the short barrels. U were vague in ur post, i read it as 155 was inferior to 175. In barrels of 24" or more ur wrong. In barrels of 20" or less u r correct . A friend's factory 24" savage barrel does 3002 with new 155 Palma smk. We confirmed bc with drops at 1k. It was either faster then my magnetospeed and chrony said or bc of .504 was on the money. All atmosphere and enviro data was used. I didn't believe the speed even after my magnetospeed backed up what my old chrony said. I nearly shit myself when it was banging steel with shooter drop using.504@3000fps.
 
#28
I never said one is inferior. Since the thread is about 20" barrels, that is the scope of my point. One needs to try the 175s and 155s (if not also some of the other options) to see what is possible if you wish to maximize performance.


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#30
155gr 308 out of a 20'' barrel w/1:10 twist?

FYI guys. Collin F. Won the .308 class at the Hide Cup with a box stock 20" Savage and hot loaded 155 Palmas.

Food for thought.
 
#34
Why does the 155 need to reach 2850 to beat the 175 out of a shorter barrel? Iam new to this. I was thinking you would want a lighter bullet .


6brshooter said:
If u can get 155 smk old Palma or ncc to 2850 the
n they will do better then 175@2650. Use the new palma smk(2156) or berger 155 , or any 155 with .500+ bc at 2850+, and they destroy175-178s. My problem with 18-20" 308 is that the ones that i had could only muster up 2750ish with accuracy. I ended up using 175s in those. I would suggest powder in the h4895 burn rate, or a hair faster, to get a little more speed in the short barrels. I tried it and 8208(temp sensitive) and still could not find an accurate load above 2750ish. But these loads were in a 18.5" ar10 and a slow poke remington barrel that shotgunned any load over2700fps.
Click to expand...
 
#36
The xbr, it's not as bad as imr4350, but in my use of 2 lbs in a couple6 brs and 308s i found it more temp sensitive then H4895. I just couldn't get accuracy or low es/sd that beat h4895 so I abandoned it. I know several people that love it, just not this shooter.
 
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#37
madarcher427 said:
Why does the 155 need to reach 2850 to beat the 175 out of a shorter barrel? Iam new to this. I was thinking you would want a lighter bullet .
Click to expand...

The BC of the 155 Lapua is around .460.

The BC of the 175 gr Sierra Matchking is .505.

Therefore, to get a better wind resistance out of a 155 gr, it's got to go faster. Environment depending, 2850 is around where that threshold is.

If you want to improve over those, there are other bullets on the market that can do better, including the newer Berger offerings.


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#38
Thank you!

tylerw02 said:
The BC of the 155 Lapua is around .460.

The BC of the 175 gr Sierra Matchking is .505.

Therefore, to get a better wind resistance out of a 155 gr, it's got to go faster. Environment depending, 2850 is around where that threshold is.

If you want to improve over those, there are other bullets on the market that can do better, including the newer Berger offerings.


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Click to expand...
 
#40
I would definitely say they work just fine. At 100 yards they were easily .5 mil with rl-15. My only issue with the 155's is stabilization out past 1000. That being said most wont shoot the 'lighter' bullets out at those ranges where the 'heavies' (175+) should be shot from a .308. I have had 175's out to 1370 yards. I just could not get the 155's to stabilize at 1000 with RL-15.
 
#41
tylerw02 said:
The BC of the 155 Lapua is around .460.

The BC of the 175 gr Sierra Matchking is .505.

Therefore, to get a better wind resistance out of a 155 gr, it's got to go faster. Environment depending, 2850 is around where that threshold is.

If you want to improve over those, there are other bullets on the market that can do better, including the newer Berger offerings.


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Click to expand...

This is slightly incorrect. Sierra does a good job at listing BC's and the 175 match king is more like .496 unless it's going out of a magnum.

.505 @ 2800 fps and above
.496 between 2800 and 1800 fps
.485 @ 1800 fps and below
https://www.sierrabullets.com/store/product.cfm/sn/2275/308-dia-175-gr-HPBT-MatchKing

I don't know what the breakdown is on the Scenar, but I've had very accurate drop charts using the right G1 or G7.

G7 ballistics 0.236 Laupa vs 0.243 Sierra
 
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