Heavy Bullets in a Slow Twist Barrel

[GermanS1]

If you're all done with the holiday festivities and need some food for thought, I just finished a new article about shooting heavy bullets (175 to 200) in a 1:13" twist barrel. I hope some of you will enjoy it.

www.riflemansjournal.blogspot.com

 

[milboltnut]

now I'm really confused...... :-[

 

[camac]

Once again a great article German. thanks

 

[JERRYHM]

Hi Herman,

Shot the Berger 185 BT LR in the Palma team test rifle Saturday (13 twist barrel).

The chronograph results:

308 Palma Team Test Rifle

Nesika action – Krieger 30” barrel, 298/3075 -- 13 Twist
McMillian F class stock, NF scope 12-42X BR

This barrel is below average for a Palma rifle barrel, the groups are larger than normal.

Barrel has been chambered for the Sierra 2156 bullet, This reamer has been renamed (Fullbore 2011)

05-29-2010
100 yard chronograph testing, Sacramento, temp = 60 degrees, humidity = 62%
Varget 2008 lot ---- Five shot groups, ten shot chronograph data.

Bullet --- Load --- Case ---Primer ---MV-----ES-----SD----- Group ---- Comments
S2155 --- 47.0 --- Lapua – 210M --- xxxx --- xx ---- xx ----- 0.351” ---
S2155 --- 47.0 --- Lapua – 210M --- 2991--- 28 ----- 08 ----- 0.269” --- 10 shots

S2155 --- 47.0 --- Lapua – 210M --- xxxx --- xx ---- xx ----- 0.609” ---
S2155 --- 47.0 --- Lapua – 210M --- 2997--- 22 ----- 06 ----- 0.712” --- 10 shots

S2156 --- 47.0 --- Lapua – 205M --- xxxx --- xx ---- xx ----- 0.627” ---
S2156 --- 47.0 --- Lapua – 205M --- 2999--- 28 ----- 08 ----- 0.558” --- 10 shots Small primers

B185BT - 46.0 --- Lapua – 210M --- xxxx --- xx ---- xx ----- 0.388” ---
B185BT - 46.0 --- Lapua – 210M --- 2821--- 29 ----- 10 ----- 0.441” --- 10 shots

Using the above MVs.
G7 BC for the S2155 --- = 0.214 ---- Wind drift 10 MPH @ 1K = 102.4"
G7 BC for the S2156 --- = 0.229 ---- Wind drift 10 MPH @ 1K = 92.1"
G7 BC for the B185 BT - = 0.283 ---- Wind drift 10 MPH @ 1K = 75"

 

[habu]

not having read the article - yet. bet german says you have to push them 'hard'.

when i shot 'palma' i shot 175's going 2869, sd 4.1, .4 moa. [13 & 12 twt]

ron ;D

 

[habu]

JERRY, THOSE ARE SOME REALLY H'HEALTHY' LOADS!!!

RON

 

[JERRYHM]

Ron,

Yea their not for the people who drive in the slow lane!

 

[habu]

JERRY,

question - presure problems??

when i went to BISLEY in 2000, i made up 190 loads to shoot 1200.

RPA 2000 190 smk, varget - 44.6 gr, vel 2790. 32", 1-12 twt. - would blow 1 out 4 primers.

later that year i was speaking with a friend that worked at WESTERN POWDERS, - he asked for and rec'd 5 loaded rounds - he tested them in their lab - he called and said - don't shoot them in a REM/WIN. - little hot -
70,000 PSI CHAMBER PRESURE.

so word to the wise.

 

[GermanS1]

I've updated the article with more results at 500 yards - Berger 155 VLD, Sierra 180 SMK and Western 197. Click here http://riflemansjournal.blogspot.com/2010/06/ballistics-heavy-bullets-in-113-twist.html and the new item is towards the end of the article.