Range Report A more realistic .308 FGMM bullet drop graph

[fenwick253]

I have notice that there are plenty of bullet drop graphs online and most of them have represented data in a huge arc. That is due to the graphs axes and the manner at which people plot their data. Most are plotted with bullet drop on the y-axis and distance on the x-axis. The relationships between these axes are rarely 1:1. So, I thought I would plot some data with a drop vs range ratio of 1:1. This would actually show realistic relationships and realistic bullet trajectory. This data is representative of the .308Win FGMM 168Gr. BTHP. I came up with the graph below. The graphs with the over exaggerated arc are not meant to illustrate the actual bullet path, but show the data in a compact graphic. Yet some people get the impression that the data in graphs is a direct representation of the bullet’s flight path. In the grand scheme of things, you can see quite flat trajectories with the .308 (in graph form).

http://tinypic.com/r/2q1xf7t/5
" rel="nofollow" target="_blank">High-res</a>

Buildings to show scale. Statue of Liberty—305.5’, Space Needle—518.8’, Empire State Building—1250’
Data gathered from http://www.ultimatesniper.com/Docs/32.PDF Created by Maj. John L. Plaster, USAR (Ret.) Based on .308Win FGMM 168Gr. BTHP with 100YD Zero.

 

[pistolpacknpete]

Re: A more realistic .308 FGMM bullet drop graph

will the 168 go 1000 yds? or do you need a heavier bullet?

 

[B2Riesel]

Re: A more realistic .308 FGMM bullet drop graph

I think you meant to ask the question differently...but I'll answer the question literally. A 168 Sierra Match King fired at even a lowly 2700 fps on a nice 70F day at 1000 feet of altitude on a 31 degree angle will fly past 5000 yards. You are pretty sure not to be hitting anywhere near of what you are aiming at...but it will get there.....eventually.

 

[FCS]

Re: A more realistic .308 FGMM bullet drop graph

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: midkansasguy</div><div class="ubbcode-body">will the 168 go 1000 yds? or do you need a heavier bullet? </div></div>

168 SMK wouldn't be my choice for 1K use.

168 Berger Hybrid or VLD, probably work just fine.

 

[B2Riesel]

Re: A more realistic .308 FGMM bullet drop graph

I don't like the 168 SMK either....generally go 175 SMK but I have been liking the 168 A-Max lately.

 

[Skigolfmike]

Re: A more realistic .308 FGMM bullet drop graph

I've been having great luck with 155 Scenars. If you can push them to ~2900 fps they are good out to 1150. They are over a full Mil flatter at 1K than 175 SMKs too.

 

[Ratbert]

Re: A more realistic .308 FGMM bullet drop graph

wow, this got off topic QUICK.

 

[axshon]

Re: A more realistic .308 FGMM bullet drop graph

OP, I like this because it gives a sense of scale and actual trajectory. Is there a higher resolution version?

I've done some digital mapping of trails and the big problem is always that you want to show both the actual ascent and descent and the entire arc of the trail. The big problem is matching up what a person sees versus what they feel that they see. This helps give context. Thanks!

 

[fenwick253]

Re: A more realistic .308 FGMM bullet drop graph

I have a high-res but photobucket resizes my images. I'll try to get another one up. Axshon, how are you doing the digital mapping?

 

[fenwick253]

Re: A more realistic .308 FGMM bullet drop graph

Updated with link to high(er)-res.

 

[B2Riesel]

Re: A more realistic .308 FGMM bullet drop graph

The hi res image does bring the point home better. Too many times I've seen bullet drop graphs that look like a roller coaster hump. I think the traditional graphs have lead to too many people making the wrong assumptions about the .308. Sure...other rounds shoot much flatter....but the thought of just 'lobbing one out there' is unjustified.

Wind is another story though.

 

[CoryT]

Re: A more realistic .308 FGMM bullet drop graph

Actually, once you get out there, it IS pretty much a lob. Look at the numbers. 300 or so inches at 900 and 400+ inches at 1000, or 1" per yard of travel. That's not precise of course, as it's a decreasing radius arc, more like .7"/y at 900 to 1.2"/y at 1K, but you see the point. For a 21" or 2 MOA target, the danger space (at sea level) is about 985 to 1013. In 13 yards the bullet will drop 10.5", hardly flat.

If you compress the scale enough, even a .45-70 looks flat out to 1K.

 

[MontanaMarine]

Re: A more realistic .308 FGMM bullet drop graph

That would be great if external ballistics were gauged against recognizeable buildings.

In the real world, external ballistics comparisons are made between different bullets at different velocities.

Anyone who would choose the 168grSMK for their 1K 308Win pursuits, is a glutton for punishment. Well, maybe not an issue if you are in La Paz.

 

[MontanaMarine]

Re: A more realistic .308 FGMM bullet drop graph

FWIW, the Empire State Building is not to scale.

Including the lightning rod, the building is 1453ft (484.6 yards) tall.

I know, trivial.....

 

[fenwick253]

Re: A more realistic .308 FGMM bullet drop graph

ah. 1453 with spire

Obviously this isn’t meant to convince anybody that the 308win is the optimal longrange cartridge. I never seen it graphed closer to scale. Not saying it’s completely true, just plotted points and thought I’d show somebody.

 

[MontanaMarine]

Re: A more realistic .308 FGMM bullet drop graph

I hear ya, I guess scaling a traj against the ESB when the intended target is generally 10-20" or so, just seems kinda pointless in my mind.

I like my 308s, but the 168gr SMK really hamstrings their potential at 1K. I'm pushing the 208 AMax at 2680 fps from a 26" 308. If you crunch those ballistics against a 168 at 2650 fps, it is night and day.

 

[DCR]

Re: A more realistic .308 FGMM bullet drop graph

Rezero at 1k yards and put things underneath the flight path at different distances. Pretty sure a 2 story house will fit at the apex of the bullet's flight path.