Range Report Apples-to-apples ballistic comparison

[kombayotch]

Sending the rifle in for a switch barrel setup. So, I was playing around with the ballistics calculator. 7-08 actually looks more attractive than 260. George's new round looks really interesting...

JBM Standard Conditions - Litz BCs (1.5" scope height). Pulled the velocities from various sources. Let me know if velocities are too far off. I was about 50 fps (or more). conservative on 308 Win. velocities obtained from my own testing.

6XC
6mm 105 Berger VLD, 3080 fps., -263" drop, 71" wind (10 MPH)
6mm 115 DTAC, 2950 fps., -289" drop, 75" wind (10 MPH)

243 Win
6mm 105 Berger VLD, 3190 fps., -241" drop, 67" wind (10 MPH)
6mm 115 DTAC, 3050 fps., -267" drop, 71" wind (10 MPH)

6mm Crusader
6mm 105 Berger VLD, 3400 fps., -206" drop, 60" wind (10 MPH)
6mm 115 DTAC, 3250 fps., -228" drop, 64" wind (10 MPH)

260 Rem
6.5mm, 130 Berger, 2950 fps., -284" drop, 73" wind (10 MPH)
6.5mm, 139 Scenar, 2850 fps., -306" drop, 76" wind (10 MPH)
<span style="text-decoration: line-through">6.5mm, 140 JLK, 2820 fps., -310" drop, 76" wind (10 MPH)</span>
<span style="font-style: italic">6.5mm, 140 JLK, 2820 fps., -292" drop, 65" wind (10 MPH)</span>

6.5-284
6.5mm, 130 Berger, 3070 fps., -257" drop, 68" wind (10 MPH)
6.5mm 139 Scenar, 2950 fps, -282" drop, 71" wind (10 MPH)
<span style="text-decoration: line-through">6.5mm, 140 JLK, 2970 fps., -274" drop, 69" wind (10 MPH)</span>
<span style="font-style: italic">6.5mm, 140 JLK, 2970 fps., -259" drop, 60" wind (10 MPH)</span>

7mm-08
7mm, 162 AMAX, 2830 fps., -293" drop, 67" wind (10 MPH)
7mm, 168 Berger, 2800 fps., -300" drop, 68" wind (10 MPH)
7mm, 180 Berger, 2600 fps., -344" drop, 70" wind (10 MPH)

284 Win (6mmbr.com)
7mm, 180 Berger, 2950 fps., -256" drop, 57" wind (10 MPH)

308 Win.
308, 155 Scenar, 2950 fps., -322" drop, 94" wind (10 MPH)
308, 175 SMK, 2800 fps., -358" drop, 98" wind (10 MPH)
308, 190 Berger VLD, 2750 fps., -328" drop, 78" wind (10 MPH)
308, 208 AMAX, 2600 fps., -352" drop, 74" wind (10 MPH)

 

[kombayotch]

Re: Apples-to-apples ballistic comparison

Hmmm. the BC for the 140 JLK is higher in the Bryan's book...

260 Rem
6.5mm, 140 JLK, 2820 fps., -292" drop, 65.1" wind (10 MPH)

6.5-284
6.5mm, 140 JLK, 2970 fps., -259" drop, 60.2" wind (10 MPH)

 

[BryanLitz]

Re: Apples-to-apples ballistic comparison

K,

I just emailed Brad about your observation with the 140 JLK. He confirmed that the BC in the library is wrong. It will be corrected in about an hour.

Thanks for pointing this out.

-Bryan

 

[kombayotch]

Re: Apples-to-apples ballistic comparison

Yeah, I meant to e-mail you about it, but got too pre-occupied specking out my build...

I tell you Bryan, when you start comparing this stuff with normalized BC numbers, you find a whole lot of surprises. This is great! It also allows you to dispells a lot of myths and misconceptions.

 

[bohem]

Re: Apples-to-apples ballistic comparison

The more this keeps coming up the more I want to build a 280 AI at some point.

 

[kombayotch]

Re: Apples-to-apples ballistic comparison

There is a reason the man who knows is shooting a 7mm RM...

 

[MitchAlsup]

Re: Apples-to-apples ballistic comparison

308, 190 Berger VLD, 2750 fps

That one might be 50 fps on the fast side.

 

[kombayotch]

Re: Apples-to-apples ballistic comparison

I've driven the 190 SMK to 2800 fps. and can seat the VLD out way more.

The 7-08 velocities are the ones I'm the least sure about...

 

[howdydoit]

Re: Apples-to-apples ballistic comparison

If the 7/08 with the amax can be run that hard its not far behind Montana Marines 30/06 208gr amax load. Could that really be right?

It runs about 100yds short of the 06 with about -100 ftlbs differnce. WOW thats alot for the 308 case.