Accuracy Question

[Old Goat]

If a rifle shoots a 1.5" pattern at 100 yards...do you simply multiply the yardage to say 500 yards by 1.5 x 5 = 7.5, or does it increase by more than simple multiplication...not factoring any outside conditions such as wind or thermals.

[Dan360]

I have found that the formula hardly ever translates out equally in hunting rifles. My ability to see with lower powered scopes/iron sights, mirage, inconsistency in the ammo, any bedding issues, etc cause groups to open up at a greater rate when I shoot from field positions with field-ready rifles. Small issues at close range magnify themselves quite a bit when shooting further out. Instead of 1 inch at 100, 2 inches at 200, etc, it might be more like 1 inch at 100, 1.5 at 200, 3 at 300, 5 at 400.

With precision built bench-rest rifles, the formula may work out. I knew a SWAT guy who had a tricked out rifle built on an M700 action that shot 1/2 inch or less groups at 100 yards. When training out of state, he shot groups at 1000 yards that measured less than 5 inches. That's pretty darn good and close to the formula.

[Hunt'nFish]

Yes. And no.
Theoritically, yes, but in practice many things also happen.
I've seen guns that shoot 1-1.5moa @100yd seem to settle in at 200 & 300yds.
So when it comes to ballistics funny things happen down range.
Hunt'nFish

[baltz526]

it might be 1 1/2" at 100yds and 2 1/4" at 300 you have to shoot it

[billc_sbio]

Originally Posted by baltz526

it might be 1 1/2" at 100yds and 2 1/4" at 300 you have to shoot it

Yeah, but practically speaking it's MORE likely to get BIGGER than smaller.

(Ya know, Murphy hangs out around EVERY corner!)

[bo4elk]

a MOA is roughly 1" at 100 yards (this isn't the exact value, but close enough). Given a group of vectors (straight lines) the originate from the same point and intersect a 1" circle 100 yards away, it can be said that they will intersect a 2" circle at 200yards and a 10" circle at a thousand yards.

But thats just the math, and a rifle's group tends to loosen the further out you go (at least that's been my experience). As mentioned, it is probably caused by a bunch of things (eye sight being an important one). If two bullets are fired back-to-back, whatever differences they have (maybe one is a few grains heavier, one is travelling a bit faster, the wind jumps up 3 mph, etc), the farther they travel the more the differences will effect the two trajectories.

[Yeti]

As stated previously, yes and no. The ONLY way you will know is to shoot it at the longer ranges. You need to keep all things equal so I always test one long range at the beginning of each range session. So one day I shoot 300, the next 200, the next 400, ect, ect. Each time I make sure I do it with the same cleaning proceedures.

I did have a 300 wm that settled down at 2-300. 100 yard groups were frustrating but minute of elk. I am sure it had more to do with the loose nut behind the stock.

[Hogwild]

Originally Posted by Hunt'nFish

Yes. And no.
Theoritically, yes, but in practice many things also happen.
I've seen guns that shoot 1-1.5moa @100yd seem to settle in at 200 & 300yds.
So when it comes to ballistics funny things happen down range.
Hunt'nFish

+1.