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overbore
05-05-2008, 07:55 AM
Mr. Bryan Litz writes in May 2008 Precision Shooting , pp15-22, of the G1-G7 BC data and many other pertinent facts relative to Sierra, Berger and Lapua 155gr 30 cal bullets. He gets all of the credit and this is is just a recap for the non-subscriber shooters.
Lapua:
fps G1 BC G7 BC Advertised BC

1500 .441 .228 Look up; may be 11% high
2000 .458 .230
2500 .473 .238
3000 .493 .242

ALL: (G7)

Sierra: .213
Berger .228
Lapua .234

Notes: "If you point the Bergers, they will have a higher BC than the Lapua's , out of the box. If you point them both, they both have have the same G7 BC of .237" ---- but at lower price from a US quality product firm with good people who improve their product lines. Overbore

milanuk
05-05-2008, 10:16 AM
Hmmm.... guess that means the mail man needs to get on the stick and deliver my May edition!

I've been enjoying the last couple editions of PS magazine a lot; more 'technical' articles like Bryan's.

I'm very much looking forward to reading the full article.

MLC
05-28-2008, 09:56 AM
I recall that Eric said the BC of the 155.5 Berger BT was higher than the 155VLD.
It should be interesting to see how it performs against the Lapua.

overbore
05-28-2008, 11:14 AM
pointed up, is, I recall, the exact same as Lapua but at a much lower cost. ;) Overbore

milanuk
05-29-2008, 12:53 AM
He was talking about the new 155.5 BT (listed BC of .486), not the regular 155 VLD (listed BC of .472). The bullet went thru testing and almost everybody who got them that I've heard from reported they shot about 1/2-3/4 moa flatter than the VLDs. These bullets are still very new and were *not* the ones Bryan tested in his review. That said... I have little doubt that 'out of the box' they'd fly somewhere between the B155VLD and the Lap154 Scenar... and the way I read his final simulation demo was that you're getting down to splitting hairs pretty dang fine to be able to actually differentiate between the VLD and the Scenar on target as it is.

bsl135
05-29-2008, 06:26 AM
The 155.5 BT's became available after I finished writing the Palma series for PS. It's unfortunate, because the 155.5 BT has a higher BC than any other Palma bullet.

It's not the extra 0.5 grain that does it, it's the length of the ogive. VLD (secant) ogive's have less drag than tangent ogives if they're the same length. However, the tangent ogive on the 155.5 is signifficantly longer than the secant ogive on the VLD, and that's why it has lower drag.

I have tested the 155.5 gr BT for BC and it's higher than the 155 VLD and the Scenar. I don't have the numbers in front of me now, but the difference is approaching what I'd call signifficant in terms of improved scoring in wind.

Here's an anectotal story that demonstrates the performance of the 155.5's...
Last weekend I shot a 3X1000 with my Palma rifle. I shot all three matches with the 155 VLD's. After completing the last match, I fired some 155.5's loaded with the same charge (46.5 gr Varget). I didn't adjust my position or the sights at all from the 155 VLD's (I had 4 MOA Left windage on). The 155.5's hit in the 8 and 9 ring, about 1.25 MOA high and 1.25 MOA left (into the wind). In other words, I would have needed 1.25 MOA less elevation and 1.25 less windage for the 155.5's. Both the VLD's and 155.5's were pointed.

The wind was 'semi-steady' and I fired the 155.5's immediately after the 155 VLD's so I consider the test to be a somewhat fair comparison, although it is anecdotal.

Of course, some of the elevation difference could have been attributed to how the barrel vibrates differently for the two bullets. The bullets were the same weight and had the same powder charge, but the VLD's were jammed and the 155.5's were jumped 0.010". Having the VLD's jammed causes a higher pressure spike which might set up a different vibration patern and affect vertical impact. I plan to write a follow-up article for PS in the near future about the actual measured performance of the 155.5 BT bullets. Needless to say, it's the bullet I plan to use for Palma from now on.

Take care,
-Bryan

henrya
05-29-2008, 06:48 AM
Bryan,

Keep writing those articles, they are very informative and you're doing a very good job presenting the information. Your work is some of the best published in PS in recent times.

bsl135
06-28-2008, 12:29 PM
In the recent past, Precision Shooting Magazine published a series of my articles on Palma bullet performance. It's been a while since the series ran, and PS is starting my new series this month (July), so I decided to make the old Palma articles available on my website. The articles are on the BC testing that I've performed on these bullets, and focuses on the difference in external ballistic performance in the context of long range slow fire competition.

Click here (http://bryanlitz.bravehost.com/) to go to my website and look for the "Palma Bullet Analysis" section on the left.

Unfortunately, Berger's new 155.5 grain bullets were not available when I wrote these articles. I plan on writing a new article about this bullet sometime in the near future.

As always, I'm open to any and all criticism and feedback.

Take care,
-Bryan