Why do my groups look like this

[Kelsey Cooter]

Check out this photo.

Iv just bought a 308, i sighted it in the other day with some factory hornadys sitting at a table shooting off bags. The bullets grouped beautifully.

Today i wanted to try some federals because they are cheaper. And they grouped strange. So i went back to the hornadys, and they grouped strange. So i did a final group with the federals and took a picture for ya's.

The scope was sighted in to the hornadys so the 1st bullet hit about 4 inches high. I wanted it to be 2 inches high so i adjusted the scope to suit. The 2nd bullet hit right where it should have after the scope adjustment. Then things went pair shaped.

Does this look like its my fault? If it were the gun or the bullet, 4 wouldnt group together like that would they?

I grew up shooting a 243 and a 25-06. But then i bought a 223 a few years ago and have used nothing bigger for years so im wondering if I've gotten lazy or something

Sorry about the long yarn

groups.jpg (97.3 KiB) Viewed 4040 times

[Member-Deleted]

Hi Kelsey Cooter it could be a number of things but what I can tell you from my experience not long ago is that
my 25-06 shot perfect one day and the next day it shot like yours what I found was the inside of my scope was loose
around the xhairs and turrets new scope fixed it
Although this may not be whats wrong with your gun just something you can check

[Kelsey Cooter]

Hi Kelsey Cooter it could be a number of things but what I can tell you from my experience not long ago is that
my 25-06 shot perfect one day and the next day it shot like yours what I found was the inside of my scope was loose
around the xhairs and turrets new scope fixed it
Although this may not be whats wrong with your gun just something you can check

Thats interesting Granddadbushy, how would i check that?

My scope is a Leupold vx2 and the rifle is a ruger 77 mkII

[AusTac]

Just spitballing but as said above scope tight? Stock not touching barrel? What are you shooting off as in do you have a solid rest of some sort? Are you straight behind the rifle?

It may not be correct or whatever but if it were me, i'd clean the rifle, check the scope tightness and stock positioning and wind it over 16 clicks ( assuming the whole 1 moa at 100y thing ) to the left and see if you get the reverse ie impact over to the left

[Member-Deleted]

Well KC how I found out with mine I shot one at center then went up ten clicks shot another then right five clicks and shot
down ten shot then left five shot then compare point of impact to first shot then went in reverse all the way back to the first
shot and shot if you have three different point of impacts with any distance between them then it could be the scope
But yours being a Leupold which are good scopes it may not be the scope but i'd try anyway
Its basicly checking the zero but if it is loose it will shoot all over the place
Cheers

[Kelsey Cooter]

Just spitballing but as said above scope tight? Stock not touching barrel? What are you shooting off as in do you have a solid rest of some sort? Are you straight behind the rifle?

It may not be correct or whatever but if it were me, i'd clean the rifle, check the scope tightness and stock positioning and wind it over 16 clicks ( assuming the whole 1 moa at 100y thing ) to the left and see if you get the reverse ie impact over to the left

Yeah scope rings are nice and tight aye. The 1st owner of the rifle was a bench rest shooter who had it bedded and free floated by a gunsmith in brissy, he told me it would shoot half moa all day long with his hand loads. He said the round count is 180 when i bought it.

When i sighted it in i sat at a table with front and rear bags. Today i started by laying down on my ute tray, but when i saw the groups i grabbed a chair and used the tray as a table and used the same bags, but still couldnt get the same result that i got when i was sighting in

[Gamerancher]

Your ute is not the best "bench". It has suspension that moves.
I reckon your scope hadn't settled after adjustment, it looks to have settled for the third shot though. Your next 3 shots went into that group, ( presuming you made no other adjustment ), which looks fine.
As for the 7th shot, shooter error? Did the rifle slip? Any number of things can send a flyer down range. Best to set up on a solid bench with good rests for sighting / shooting groups. Without consistency you'll never get a true idea of what's going on. Hard to tell too much from 7 shots.
Another thought, is your scope centered? I recently had to help a bloke with a scope that had been wound all the way to the side to compensate for a badly off center set of mounts. Any change in elevation also changed windage and accuracy was non-existent. Removed the scope and centered it and modified the mounts so that we could sight it in without using too much windage adjustment. Fixed his problem.

[COLLECTOR 1]

What barrel weight are we talking about.... after the bed and float being done is it a case of the barrel heating up,and wandering. I've seen over the years that sportier or light weight barrels heat up very quickly and will wander so chronicly. Also how long between shots...????...What sort of rifle is it..?????...

Just a starting point...

Collector 1

[COLLECTOR 1]

Sorry just re read the thread....lol... ruger 77.... if it's a timber stock first generation type check the tension on that angled screw at the rear of the trigger guard...I doubt if it's scope ( leapold) nor the mounts... they are time proven....

Collector 1

[Kelsey Cooter]

What barrel weight are we talking about.... after the bed and float being done is it a case of the barrel heating up,and wandering. I've seen over the years that sportier or light weight barrels heat up very quickly and will wander so chronicly. Also how long between shots...????...What sort of rifle is it..?????...

Just a starting point...

Collector 1

From what i read in the net last night I think you might be right Collector, my barrel is a 22inch sporter, how hot is to hot? I didn't have alot of time last night so i was letting them fly fairly fast. Iv never had to think about the heat with my 223, it doesnt change at all as it heats up.

[straightshooter]

Before you start pursuing exotic potential problems, as may be suggested by well meaning people, the first thing to do is eliminate operator error.
Have you developed a flinch or possibly are you flinching in a different way with a 308?
A 308 can be tough to shoot with fine accuracy under some circumstances.

[marksman]

you have been given a lot of good advice here
what I would ask is "have you had the rifle apart?"
then make a list and check the rifle/scope over and clean the motherfarker good and proper,
make sure the magazine box is floating, it has to have movement in it, and the middle screw is not tightened up just snug so it wont fall out!
by the way if you have had the rifle apart the rugers are supposed to be tightened to 95ft lbs at the angled king screw
I don't tighten my rugers to this amount and definitely would not on a plastic stock, I also would not tighten the rear screw as much as the front and would check for the action bending while being tightened up
then slowly start again with one brand of ammo only, making sure you are not the problem, shoot it prone with a rear bag, slowly

I have seen this because of : running in a factory barrel (can take up to 80 shots before it will settle down that I've seen if there are burrs in the bore),
a loose scope or action, mag box not fitted correctly in a ruger, middle bolt tightened up to much, oil between the action and a synthetic stock, a type of ammo the rifle does not like and ammo that is not concentric (roll your ammo on a pane of glass, glass table ect looking at the tip and see if it rolls or wobbles)

if your rifle shot well it should again, good luck with it all

[pomemax]

First post you said you were shooting of bag ? I have seen it a few times of the bench someone shooting of a bag slips back a bit barrel on the bag not stock the they wonder why the grouping are going weird (Just a thought )

[Gwion]

Strip the rifle. Check for shiny rub marks on both metal and timber. Give it a bit of a clean externally. Put it back together with correct torque on kingscrews.

It is possible that you are not riding the shooting bags correctly, such as allowing a sling swivel to contact the front or rear bag. Also, as Gamerancher suggests, your car is not a shooting bench which can compound any faults with the shooting platform, ie: bags and rifle and how they are set up.

[Kelsey Cooter]

Thanks everyone for your help. I stripped her down yesterday, discovered the magazine box was not in the correct spot and was jammed hard against the reciever instead of free floating as Marksman said might be the problem. Fixed her up and used a proper table to shoot paper again yesterday and the same bullets grouped well within 1 inch.
This is an awesome site for getting help like this

[Wm.Traynor]

Onya Kelsey

[marksman]

I'm very glad to see it worked out for you

[Gwion]

Good news, mate.