how far off is the shot at 100/300/600


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bear guide
April 4, 2012, 01:19 AM
if your shot is off by one inch at 100, how far off will it be at 200, 300 etc.
example- one inch off at 100, two inch off at 200, 3 at 300 etc. (linear)
or is it exponential 1 inch at 100, 300 4 inch, 600 8 inch ?
what happens at 900 ? nine inchs off, or more ?

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bpk1
April 4, 2012, 01:51 AM
I would imagine that to answer that properly, people would need to know the caliber/grain, and powder to determine that drop accurately.

JohnKSa
April 4, 2012, 01:56 AM
If there's no wind and you're just talking about an aiming error or point of aim/point of impact error, then it's linear.

A 1" error at 100 yards would be a 3" error at 300 yards.

If you're talking about wind or other effects, there's no simple answer without providing information about the projectile/velocity/rifling twist/conditions/etc./etc..

egg250
April 4, 2012, 02:11 AM
Hard to determine. A rifle/cartridge combination that is capable of shooting 1 MOA at 100 yards is not necessarily capable of shooting the same at increased distances. That group may open up to 1.5 to 3 MOA at 300 yards and expand even more the farther away the target. Too many variables to account for. The way to figure it out is to shoot at various known distances and determine the margin of error, which might allow you to estimate the spread as you increase distance.

ZGunner
April 4, 2012, 02:40 AM
http://www.remington.com/pages/news-and-resources/ballistics.aspx

This is a pretty good ballistic calculator. It should steer you in the right direction, at least gives you the drop you're looking for.

allaroundhunter
April 4, 2012, 02:54 AM
Vertical trajectory is a function relating to gravity, which is constant at about 9.81 m/s/s or 32 ft/s/s (not linear).

However, there are other non-constant variables that make it not as simple of a calculation as you are wanting.


I sight in my .270 to shoot about 1.25" high at 100 yards and that makes it dead on at 200. This means that it will impact about 2.5" low at 300 yards (again, just talking elevation here, not accounting for wind or anything else).

JohnBT
April 4, 2012, 09:05 AM
Bullets don't fly a straight arc always, some (all?) of them corkscrew through the air. The result can be better groups at 200 yards than at 100 yards.

Google some terms like "better shot groups at 200 yards than at 100 yards" and read some of the threads.

mljdeckard
April 4, 2012, 09:14 AM
My experience reflects that of allaroundhunter precisely.

mdauben
April 4, 2012, 11:52 AM
I think people are talking about two different things. Most of the posters seem to be addressing trajectory, while the OP was asking about accuracy. Two different, and generally unreleated, topics.

If we eliminate human and environmental factors, then yes, a gun that groups 1-inch at 100 yards should theoretically group 3-inchs at 300 yards. Now, since there are a lot of other influences on accuracy than just the gun's inherent capability, you probably won't achieve that perfect 1:100, 2:200, 3:300, etc. progression, but ideally you should.

JohnBT
April 4, 2012, 12:25 PM
Yes, although some gun and bullet combos will shoot better groups at longer distances than at the shorter distances. External ballistics can be, shall we say, challenging.

John

Jeff H
April 4, 2012, 01:40 PM
If we eliminate human and environmental factors, then yes, a gun that groups 1-inch at 100 yards should theoretically group 3-inchs at 300 yards. Now, since there are a lot of other influences on accuracy than just the gun's inherent capability, you probably won't achieve that perfect 1:100, 2:200, 3:300, etc. progression, but ideally you should.

Yes.

I MOA is still 1 MOA at either 100 yards or 600 yards. So as long as you have a gun that will shoot the same 1MOA at 100 and 600, you can be 1" off at 100 yards and 6" at 600, but there are many more things to consider as mentioned by many others above.

pseudonymity
April 4, 2012, 06:21 PM
The deviation from the point of aim is almost always going to be larger than a linear progression, but I would not expect anything like exponential. Even with all other factors constant, the deviation between point of aim and point of impact will tend to increase with distance. With all other factors being the same from shot to shot, the deviation should be linear with respect to time of flight, but not necessarily distance.

Assume a rifle in a vise and cartridges loaded as identically as possible. Conditions are stable and perfect, 100 to 600 yds out. The bullet starts to lose velocity as soon as it leaves the barrel so it takes X msec to reach 100 yards. Since the bullet and barrel are not perfect, the impact at 100 yds will be a bit variable. Lets say that the bullets are not perfectly concentric, so they tend to "wobble" in flight. Since the bullet takes longer to go from 500 to 600 yards (X + Y ms) than it did to go from the muzzle to 100 yds, it has more time get effected by whatever problems it encounters.

JohnBT
April 4, 2012, 10:22 PM
www.nennstiel-ruprecht.de/bullfly/index.htm#Figures

There is a lot of good info on this site. Look at yaw for instance, the tip of the bullet does not follow a straight path, but a helical path. There's a lot more complexity to a bullet's flight than it would seem at first glance.

John

bear guide
April 6, 2012, 11:02 AM
thanks for the input

bear guide
April 6, 2012, 11:14 AM
i was reading an article on rocslide.com about understanding rifle performance through standard deviation, and i was questioning some stuff. thanks for your educated input.

http://www.rokslide.com/2012-01-09-05-12-00/firearms/193-understanding-your-rifles-performance-through-standard-deviation

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