theoretical limits


PDA






SSN Vet
May 10, 2006, 01:33 PM
disclaimer....I'm not a gunny, not a sniper, not verry experienced with rifles at all.

I am an engineer, who is interested in all of the above topics however, and I enjoy very much the "factual" discussions on this forum.

So here's my question....

What are the theoretical limits to how far a visually sighted projectile can hit a target and what are the factors that go into this.

Theory set aside...what would be considered a long (but achievable shot) with current technology.....(say a AI 300WM and top shelf shooter).

If you enjoyed reading about "theoretical limits" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
taliv
May 10, 2006, 01:41 PM
curvature of the earth would have to be my top constraint for visually sighted systems

Bartholomew Roberts
May 10, 2006, 01:45 PM
In 1879, they used an iron sighted .45-70 to hit a target two miles away (http://www.researchpress.co.uk/targets/sandyhook.htm) (a fun fact to bring up the next time someone squawks about the .50 BMG).

Vern Humphrey
May 10, 2006, 02:11 PM
There are three limitations:

1. Acquire and identify the target.

2. Determine the range and apply corrections.

3. Determine the effect of wind and apply corrections.

With modern firearms, laser range finders and wind sensors, hiting a man-sized target at over a mile is certainly possible. With time to prepare, one can mark ranges -- that is measure the distances by lasing or pacing and use either artificial or natural markers to indicate range.

Proficient shooters can use grass, dust or mirage to determine wind conditions down range.

Zak Smith
May 10, 2006, 03:53 PM
Modern rifle bullets do strange and sometimes unpredictable things as they pass through the Mach 1 velocity range (the "transsonic region"). This is why long-range target shooters always try to ensure their bullets are still solidly supersonic at the target distance.

Once you get past 1000 or 1200 yards, a lot of things you can pretty much ignore or take for granted from 0-800 become important. A low velocity S.D. is important. The right twist for the projectile is important. The yaw and precession rates are important. Spin drift can be important. Atmospheric density and temperature are important.

But even if all those are perfect, to accurately predict the bullet's impact point, the shooter would need to be able to accurately measure the exact wind throughout the bullet's path. Thus the crux of long and extreme long range shooting usually comes down to wind estimation.

A shooter with a 300WM should be able to make a hit on a 1-2 MOA target at 1600 yards if he judges the wind correctly and has everything else right. For some 300WM loads, 1600 is right at the trans-sonic limit (2000' ICAO density altitude, 210gr Berger VLD, 2900fps)

-z

If you enjoyed reading about "theoretical limits" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!