Anyone here understand rifle ballistics?

[Jerk]

I did a number of 5 shot groups today.

At 100 yards, my group was about 1.5 to 2 inches.
At 200, it was about 2 to 3 inches
At 300, it was was 1.5"

Isn't that a little ***-backwards?

Kind of wierd.

I just don't understand that.

It's normal for a bullet to stabilize at over 150 to 200 yards and the groups to shrink relative to range, but to literally shrink is odd. The group at 300 yards was smaller than the one at 100. It makes no sense. Still, a 5 shot 1.5 inch group at 300 from a semi-auto (AR-15 in 6.5mm) is okay by me. If that's a prairie dog, it's dead.

I think it is parallax from my scope that's the problem.

[GottaHavePride]

Hmmm. Aside from :mack: tricky wind! all I can think of is maybe your heart rate stabilized? I know competition-grade shooters time their shots with their heart rate so their heartbeat doesn't throw off their accuracy...

[Jerk]

Hmmm. Aside from :mack: tricky wind! all I can think of is maybe your heart rate stabilized? I know competition-grade shooters time their shots with their heart rate so their heartbeat doesn't throw off their accuracy...

Now that just adds a whole new variable to this problem. Thanks :mad:

[GottaHavePride]

And your breathing. Don't forget breathing. ;)

[Mjcpr]

At 100 yards, my group was about 1.5 to 2 inches.
At 200, it was about 2 to 3 inches
At 300, it was was 1.5"

That's pretty weak, but I'd go with 200 and hope you last a long time or something.

[Curly Bill]

Did you shoot the 100 yd groups first? and from a clean barrel? If so that could be the deal, a lot of rifles will shoot better after they've had the barrel fouled by shooting some rounds through it.

[KABOOKIE]

This has little to do with rifle ballistics and more the shooter's ability. To accurately determine the problem here I'm gonna need more samples. I recommended more shooting.