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View Full Version : Palma bullet choice.


Savage99
December 3, 2005, 01:25 PM
What is the bullet brand of choice today? The Sierra SMK has been standard but the Lapua 155 Sencor has a higher "published" ballistic coeficient.

Thanks

Jim Watson
December 3, 2005, 01:29 PM
Not my event, but lots discussion at
http://www.long-range.com/forums/index.php?showforum=32

I think you are going to have to do all that tiresome loading and shooting to pick the one most accurate in your particular rifle. Information not available on Gorenet.

T. O'Heir
December 4, 2005, 12:17 AM
"...a higher "published" ballistic coeficient..." Whoopee. Doesn't mean your rifle will shoot them well. Wouldn't hurt to work up a load for them though.

Zak Smith
December 4, 2005, 01:07 AM
I have shot over over 2500 of the 155gr Lapua Scenars through my AI-AWP rifle, in factory and hand-loaded ammunition. I use the published BC value of 0.508 along with the actual measured muzzle velocity from my rifle and appropriate environmental conditions as inputs to any of the ballistic calculators such as Sierra or Exbal. These produce drop values which I have verified within about 0.5 MOA out to 800-825 yards at an ambient altitude of 5000'. (I say accurate within 0.5 MOA because most of my targets are right around 1 MOA at those distances, and the data was proven by making hits on steel.)

This would suggest that the published BC value is accurate. Some guys over on Long-Range.com have posted similar experience.

The 155 Scenar definitely is more sensitive to barrel/chamber setup than a more common bullet like the 155 SMK. Neither my old AR10 (20") or a friend's LTR would shoot the Scenars worth anything. My AWP has shot its best groups (I'm sure limited by my ability) with the 155 Scenar, however (between 0.2 and 0.3 MOA - would have to check logbook for exact size).


The 155 Scenar's high BC looks suspect until you place one next to a 175SMK-- the 155 is a longer bullet.

atek3
December 7, 2005, 01:37 AM
how is the 155 longer than the 175? Secant versus tangent? "Pointy-er"?

atek3

Zak Smith
December 7, 2005, 01:45 AM
It's just over 0.050" longer than the 175SMK. Here's why:

http://apollo.demigod.org/~zak/DigiCam/scenar/small/154_5454_img_c.jpg (http://apollo.demigod.org/~zak/DigiCam/scenar/?medium=154_5454_img_c.jpg) [ link to LARGER image ] (http://apollo.demigod.org/~zak/DigiCam/scenar/?medium=154_5454_img_c.jpg)


The first 2/5ths of it is hollow.

atek3
December 8, 2005, 03:08 AM
you suck at sectioning bullets...

j/k

atek3