1 inch @ 100.....1 3/4 inch @ 200!!??

[.308--win]

A question for some of you seasoned handloaders, How do I get a 1" group at 100yrds and a 1 3/4" group at 200yrds!? I'm no ballistics expert, but would one think that a 1" group would be ~3" + at 200? Some info on my load, 7mm-08, 140grn Sierra Pro Hunter, over 38grn of H4895. No chrony, ~2620+fps according to book. Just wondering if this sounds right to you guys! Thanks for your input!!

Perry

 

[Ormachek]

Twice the distance, twice the group....I don't see the problem here.....

 

[acrashb]

A 1" group at 100 equals a 2" group at 200,3" at 300, and so on.

Why would you get a slightly tighter group than expect at 200? Natural variance. It's not like you'll shoot 1.000" five-round groups all day long. Some will be 1.25, others .80, and so on. So you shot a good group at 200 and a slightly less good group at 100.

 

[bill c68]

but that's what he is saying... he is shooting better at 200 than 100. Is this consistent or just a one off? My guess is mental and you are more careful at 200.

 

[.308--win]

Thanks guys, just thought that it might be a little bigger group at 200, guess I'm finally getting the hang of this loading and shooting addiction!!

Perry

 

[.308--win]

My guess is mental and you are more careful at 200.

You could be right, subconsciouslly making myself pay more attention to the shot!?

Perry

 

[gabrielguitars]

There is also the issue of bullet stability. I have personally had loads that shot smaller groups at 200 m than at 100m. The bullet has not had enough time (distance) to stabilize. Beyond that, my .308 with the same load printed 1" at 200, 1.25" at 300, and 2" at 400. Who knows?

 

[Longshot]

Some loads settle down after a bit of distance and shoot better.

 

[Ganderite]

Could be barrel harmonics. the muzzle is flipping when bullet exits.

It is either moving up or moving dow as bullets exits. If moving up, the slightly slower bullets (which would usually be the bottom bullets in the group) will be launched aimed higher (muzzle is higher).

This is a well know issue known as "compensation". Positive compensation is important for long ramge performance with mediocre ammo. If your velocity SD is single digit, compensation is not really required.

 

[Dogleg]

Many scopes are closer to parallax-free at 200 then they are at 100.

 

[liberty]

Many scopes are closer to parallax-free at 200 then they are at 100.

X2, does your scope have fixed or adjustable parallex....

 

[Mr.4x4]

Seems you the Force is strong in this one....

 

[icedragonmx]

My best 100 yard group today was .82moa, my best 300 yard group was .78moa and my best 500 yard group was .54moa- Go figure Some days are just like that.

 

[Randy B]

Wind blows them in as well as out!!!

 

[manitou210]

Scope Paralax

Many scopes are closer to parallax-free at 200 then they are at 100.

x2
manitou

 

[ben hunchak]

You'll find most on here get smaller groups the further they are away.

 

[Rod B]

You'll find most on here get smaller groups the further they are away.

I must be doing something wrong; mine get larger at longer distances.

 

[matty86suk]

I must be doing something wrong; mine get larger at longer distances.

me too, my best 3 shot group is .470 at 100 and 1.220 at 200, i suck more than most though...

 

[CyaN1de]

Shoot 10 - 5 shot groups at 100 and 10 - 5 shot groups at 200 and compare the averages. This would be a far better comparison than basing it on one group at each distance.

 

[horseman2]

It is due to the "Yaw" factor.
The base of the bullet has "YAW" as the bullet is upset coming out of the barrel and for the first little while the base is rotating around the axis.
As it settles down it starts to spiral. If you did more testing you would find a point where they all went through the same hole. Yours may have already occurred but it might be beyond the 200 yard mark too.
And you do not have to be a veterinary surgeon to recognize horse manure . . .