Bad horizontal stringing all of a sudden.

[Metzger]

Hi,

I have a remington 700 LR 7 rem mag. It is a very consistent 1/2 moa or better shooter 2.5" 3 shot @500 best is 1.25" @ 500 yards.

About three months ago I all of a sudden started getting a horrible almost straight horuzonal stringing.
I have started to rule out some things.
1. I remounted mounted the scope, base and rings. NO change.
2. Changed rings and base. NO change
3. Rebeaded gun. Front and sides of the lugs not beaded NO change looks worse?
4. Change rings and base to old original NO change.

So now I sent scope to manufacture and which they saw it checks out ok.

I spoke with the manufacturer/distributor and they suggested to check/tune the action screws. Has anyone found this to help?

 

[Metzger]

Picture is sideways.

 

[Metzger]

Again.

 

[Barrelnut]

Seems you have sorted thru the scope/rings/rail pretty well.

"Tuning" the action screws can help tighten groups and such by changing stresses on the action but this is more of a fine tuning aid. Your groups seem beyond what that would help.

I would think it has to do with the action shifting in the stock during recoil. Did you do a completed bedding job on the rifle? Did you bed it before or after the stringing started?
Looks like the action screws are simply not tight enough. Are you checking them with a torque wrench type tool or just hand tightening them? You might even have loose pillars in the stock. All aspects or stock to action fit need to be looked at closely, IMO.

 

[Metzger]

Action screws always torqued by hand what seems tight.

It was beaded day 1 with the original stock then changed stocks and rebeaded 1/2 moa or better then three months ago this started.

 

[Barrelnut]

That's a crazy problem. When I have had scope or ring problems the shot patterns would be kinda random. Not just moving in one direction like that. Is it movement linear? Like each shot moves further to the right or left?

Might want to consider getting a Wheeler torque wrench like below so you can gauge the tightness of the action screws. I would try both at 45 inch pounds first, shoot, and then tighten both to 60 or 65 inches and try again. That much torque shouldn't hurt a bedded stock.
http://www.amazon.com/dp/B0012AXR4S/?tag=lrhmag19-20

 

[ColoYooper]

Very curious...How are you shooting the rifle? Off of a lead sled, or a bipod, or a cheapo rest, a sandbag, etc. Is your support contacting a sling or swivel stud? What are you using for rear support? Somehow I expect there is something not quite right in your setup. Is your trigger set to 35lbs? (just kidding)

 

[Metzger]

Very curious...How are you shooting the rifle? Off of a lead sled, or a bipod, or a cheapo rest, a sandbag, etc. Is your support contacting a sling or swivel stud? What are you using for rear support? Somehow I expect there is something not quite right in your setup. Is your trigger set to 35lbs? (just kidding)

Harris bipod, sand bag in rear, 2.5lb trigger pull. I have done alot of 1/2moa groups at 500 yards like this.

 

[ColoYooper]

OK, it sounds like it's nothing you are doing. This happened to me in the Vertical direction. I had the transport break on my Leupold Mark IV and it would string upwards. I sent it back to Leupold and they re-built it. What scope do you have? I know you sent it back to be checked but not all manufactures are equal...

 

[NW Hunter]

Metzger, are you reloading for this rifle? Just throwing this out there.

Normally, horizontal stringing is a bullet seating adjustment.
Have you recently checked to see if your measurement to the lands has changed?

Two things to look for are throat erosion or a carbon ring in the throat.
I had a rifle's groups go sour once and found a carbon ring caused the measurement to the lands shorten by .006".

Just another thing to rule out.

 

[NW Hunter]

You got me thinking now.
Have you inspected the stock for any hairline cracks?
Check the recoil lug for cracks?
Has the barrel come slightly loose from the action?

 

[Metzger]

OK, it sounds like it's nothing you are doing. This happened to me in the Vertical direction. I had the transport break on my Leupold Mark IV and it would string upwards. I sent it back to Leupold and they re-built it. What scope do you have? I know you sent it back to be checked but not all manufactures are equal...

Sightron

 

[ColoYooper]

From your photo you have a very nice group vertically, and bedding, torquing, reloading, wear, problems would appear in both vertical and horizontal dimension...maybe one more than the other, but not 100% in one and 0% in the other. If possible, try another scope and see if your problem goes away. When I had the vertical transport scope problem, my groups were like that...except they were perfectly straight vertically.

 

[cowboy]

Have you looked at your muzzle cone under a magnifying glass? You may have a very minor nick right at the exit of rifling - not saying you did it but cleaning rods/jags are not known to be friendly with muzzle exit.