What Causes Horizontal Groups?

One last thing with a "skinny" barrel or any barrel for that matter especially if you hunt. KNOW your COLD BORE IMPACT POINT.
 
All you guys that are talking about scope shift, bedding, etc, bull. HE SAID IT WALKS TO THE RIGHT. The things you mention would cause random shifting of inpact. There is only one thing that I can think of that causes a consistant walk to either side is a barrel that has a bore out of center with the OD. Heat causes one side of the barrel to expand and lengthen a tiny bit causing the poi to shift. Been there done that. If you haven't shot a rifle that acts this way you don't know what you are talking about. Yur just gussin.

Donald
 
Actually while your situation is right most of the others are also.
I currently have a scope issue that causes them to walk to the right on a br gun.
A friend had a ruger in 220 swift that did it and it was a bedding problem. Factory bedding in the barrel channel.
These 2 are facts so it just goes to prove there can be more than one possibility.
 
Wildman

I dont remember if you said what brand this gun was, however....
If it is one of the American brands (and yes I know some are made elsewhere) if you have not modified the gun or stock you can contact them and talk with them about it. I know Ruger and several others will have you ship the gun back to them and they will fix or replace it free of charge. You would have to pay shipping but it would sure be the easiest fix.
IF its a stock or barrel issue thats on them.
However before you do, borrow another scope and make sure that the scope is not the issue.
It will be helpful if you can scan a couple of targets to send them.
I have had several friends in the past who have done this.
 
Donald said:
All you guys.............................................. If you haven't shot a rifle that acts this way you don't know what you are talking about. Yur just gussin.

Donald
Click to expand...

We're all just guessin' Donald.

Including you :)

al
 
Guys, just stop. Donald has figured it out. Some "GUN PLUMMER" done went and chucked the barrel blank sideways in the deep bore machine and bored the hole sideways. The rifling criss-crossed on the right side inside the bore. I thought that was it but was afraid I would sound like an idiot!!!!!
Wildman ask Donald if you can borrow his bore stretcher and grove straighteners, and don't forget the wind grease you'll need it.
And We still don't know what WILDMAN has but it's WILD!!!!!!!!
 
OK. Here is the situation: I have a Winchester Model 70, .325 WSM, all stainless steel, 24" long barrel, 1:10 barrel twist, bullet seating depth is .005" off the lands, I am shooting 200 gr. Nosler Accubond bullet. This rifle was purchased for elk, moose, and bear hunting and has a standard barrel (not a bull barrel). The scope is a Leupold Vari X - III 3.5-10x variable power without a parallax adjustment. The scope base is a one piece Leupold. I was test firing three different loads at 100 yards using the same bullet but a different powder. The wind was extremely light 0-5 mph and the humidity was 95%. The temperature was 88°F. I have shot competitive benchrest for several years so I consider myself a decent shot. The three different powders was Reloder 17, H4350, and H4831sc. I started with the Reloader 17. The first shot was at six o'clock, the second shot was to the right and the third and final shot was even further to the right. All three shots didn't vary more than 1/8" vertically but horizontally was nearly 2.5"!!! After three shots the barrel was hot enough you wouldn't want to leave your hand on it. After allowing the barrel to cool off to near normal temperature I shot a three shot group with the H4831sc and the results were nearly identical to the Reloder 17. Once again, I allowed the barrel to cool and shot a three shot group with the H4350 powder. This time I allowed a little more time in between shots. The first shot was at six o'clock, the second was 3/4" to the right and the final shot dropped opening the group up to 1 1/4". I am still not happy with the results but I think I can improve on it. I have been shooting IMR-4350 and have shot 1/2" groups on days with good weather conditions. I am only experimenting with these powders to see how well they would shoot. So I know the gun is capable of shooting small groups. So...what is causing the horizontal groups?
 
al,
you are right on again.....we are all guessin. But I bet I am guessin closer to the problem than any one else. Especially since it does the same thing every time. Those skinny barrels and overbore cartridges put a lot of heat in a barrel real fast. Don't take much off center bore to walk the bullet across the target. And they are all off center to some degree.

Dave10x,
If you would talk to me real nice I might, just might let you borrow my bore stretcher. lol. But I would loan you my big sledge hammeer to make that bugger straight. Or maybe oval.
 
Donald said:
al,
you are right on again.....we are all guessin. But I bet I am guessin closer to the problem than any one else. Especially since it does the same thing every time. Those skinny barrels and overbore cartridges put a lot of heat in a barrel real fast. Don't take much off center bore to walk the bullet across the target. And they are all off center to some degree.
Click to expand...

I can't disagree with your reasoning :) you might have hit it.

al
 
FBecigneul,

Using the Nosler Handloading Manual, all of the loads are within the specified limits for grains of powder. However, they are on the hot side but not at the maximum allowed.
 
TestPilot said:
This post give some insight on horizontal stringing/seating depth
Click to expand...

This is exactly the sort of horizontal stringing I said was IMO NOT the problem up in my first post. I do not believe it to be a "tuning" thing. Ever since BR guys discovered tuning the whole world has jumped on the bandwagon.

Wrongly IMO

I don't give any credence to the ideas set forth over on the other forum.

al
 
TestPilot,

Please see response #28 from Wildman on page 2. That will explains the situation. If you need more info after reading it please reply back. Thanks for your interest.
 
One other item which may be of interest..... it is my opinion that the barrel in question would be hammer forged which precludes any sort of eccentric or off-center bore.

Hammer forging is often implicated though in "leaving residual stresses in the barrel."

guessin' here

al
 
Donald said:
al,
I think you touched on it. I assume this is a hunting rifle with the usual pencil thin barrel. If so, then the barrel is probably walking due to heat build up.


Donald
Click to expand...

I just had the exact issue as Donald stated. I had a Sendero barrel that would "walk" from target center to 9 o'clock @ 2" at 200yards as the barrel heated up. Once the barrel was warm, the group would stabilize at about 1 " at 200 yards. Very aggravating, I'm replacing the thin factory barrel with a Krieger Heavy Varmint (currently 6 months to get a barrel :( )
 
When everything seems correct and after you rule out wind and scope issues most of the time I have found the unknown horizontal spread was due to an issue with the rifle. Usually bedding. And the most common location of the problem was at the base of the recoil lug or behind the recoil lug. If the rifle seems to want to shoot to two different points of aim make a careful check of the bedding. A very small bedding error can make for a big error at 100 yards, even with the light recoil of a PPC or a BR case.
 
Wildman, is that a one-piece leupold base with the coarse windage adjustment at the back end? If so, trash it, and slap on a one piece Picatinny rail. bed it. you will have eliminated a variable. Seymour Fish
 
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