7mm-08, 120's vs 150's to 1000?

[Brians708]

Intro:
Cal= 7-08, I have shot my pet load with 120gr NOS BT for years and love the performance. In the past I have messed with a 150 smk and it was ok. Now I want to take it (the gun) past 600 and out to 1000 (the 120’s shot 4” at 600). So I thought I must need the 150smk or similar and that the 120 would be out of the question. I have spent the last month working on fire forming 100 cases and tweaking the 150smk. Right now it is running ½ min at 300 and I have not shot further yet.
The Question:
So the other night I am at the bench logging my last results/ reviewing cases and for grins decided to compare the 1000 data from BulletFlight ( Iphone app) for both the 120 and 150.
Crap, I think I burned a lot of time for nothing……

BulletFlight Data:
Elev 800, temp 90 deg, 10mph from 9:00.

120 Nos- BT, 3017 fps, @1000 yds it should be, 20 moa-elev, 3.8 moa Wind , going 2038fps and have 1107 fpe.

150SMK, 2823 fps, @1000 yds it should be, 34 moa-elev, 9.6 moa Wind, going 1260fps and have 529 fpe.

The data are hard for me to believe. Anyone want to run this on their calculator and tell me if something is hosed?

 

[Jeffvn]

Re: 7mm-08, 120's vs 150's to 1000?

Quick target says:

150 - 1000 yard data = 33.25 MOA elevation from 100 yard zero; energy 554 lbs; 9.0 minutes drift in 10 mph cross wind;

120 Nos BT - 29.00 MOA elevation; 489 energy; 8.5 MOA drift in 10 mph cross wind.

JeffVN

 

[ChadTRG42]

Re: 7mm-08, 120's vs 150's to 1000?

168 Berger VLD, or a 180 VLD if it will fit.

 

[craigp40]

Re: 7mm-08, 120's vs 150's to 1000?

Using my calculator, this is what I show:

120 BT @ 1000yds needs 31 MOA elevation, 468 ft/lbs energy and 8.8 MOA of windage.

150 SMK @ 1000 yds needs 35.5 MOA, 527 ft/lbs and 9.3 MOA for wind.

If you're going long range with this cartridge, forget both the 120 and 150 and step up to the 162 Amax or 168 Berger. You'll get much better performance.

 

[ChadTRG42]

Re: 7mm-08, 120's vs 150's to 1000?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: brians708</div><div class="ubbcode-body">120 Nos- BT, 3017 fps, @1000 yds it should be, 20 moa-elev, 3.8 moa Wind , going 2038fps and have 1107 fpe.</div></div>
Yes, this data is not correct. I show 31.74 MOA to 1K and 9.92 MOA of wind with a BC of .417

With a 168 Berger VLD at 2640 (which you should be able to get a little more), you should run about 32.82 MOA to 1K, and 7.05 of wind with a BC of .617. A lot less wind drift, which is what will get you.

 

[Brians708]

Re: 7mm-08, 120's vs 150's to 1000?

Thanks all, I knew the 120 work up had to be incorrect.

 

[sandwarrior]

Re: 7mm-08, 120's vs 150's to 1000?

Why don't you try looking at the 140 Bergers in that cal? Personally I use 168's in my 7x57 which is about the same ballistics. From a long barrel I only push them out at 2660 fps. I'm thinking a lot of the extra velocity comes from the longer barrel. Not necessarily how hard I push them.

Anyhow, something else to think about is I ran the numbers on JBM and here is what I came up with. Same elevation and temp as you, but added 70% hum. Std. pres. won't change all that much at that low of altitude, about 1-2"@100 difference. Temp is the big factor. Used a 0.0, 100 yd. zero. with a 1.5" high sight. All figures are in MOA

Anhow:

120 Nos BT @ 3017 = 35.4 drop and 10.1 wind
<span style="color: #3366FF">140 Ber VLD @ 2900 = 33.2 and 8.1</span>
150 SMK @ 2823 = 40.1 and 10.5
<span style="color: #FF0000">Ber 168 VLD @ 2650 = 35.4 and 6.8</span>

As you can see the VLD seriously outperforms either of the other two in wind. I've only tested half a box with the 140 Ber VLD's but they look promising for the increased velocity. The Sierra MK's tend to be very accurate bullets. But, if you compare them to a Berger you will see just how much more streamlined the Berger is. That is why you don't come up with great numbers @ 1k for the 150. I've shot some of them and more than 750 of the 168 SMK's and I will tell you the bluntness of their tips kills them at extended ranges. Their accuracy is inherent though as the shorter ogive is much more forgiving as to variations in loading and individual bullets themselves.

Note: I went a little conservative with the Berger velocities as I don't know how hot you might load them.

 

[Brians708]

Re: 7mm-08, 120's vs 150's to 1000?

Thanks, I may try the 140 berg's... might be a good trade off wind drift gain and less recoil from the heavies... Until I get a can for it anyway. After being behind her with the 150's running hot I can get a little beaten up! For now I will stick with the 120's as they are not near as punishing on recoil and damn they shoot good out of this rig... But I will definitely shelf the 150's for this game.....