Why the vertical stringing?

[jb1023]

I have been doing some load tests but keep getting vertical stringing and I don't know what it could be.

Please ignore the 2 strings I have crossed out as something came up while at the range and they were rushed.

Also, the final target is 5 shots rather than 3 as are the first 2 targets.
Target 1 was shot 9/24/2016
Target 2 was shot 10/1/2016
Target 3 was shot 10/8/2016

 

[North Idaho Hunter]

I've had similar issues due to not having a solid rear support and the stock dropping upon recoil causing the vertical. It becomes even more evident with my large magnum guns.

 

[rcoody]

What caliber and barrel contour?

Heat is usually the issue

Or a not completely free floated barrel

 

[tbeasley]

A couple of things to look for;
-check your rear bag. Is it solid and level, does it rock back and forth. REMOVE swivel stud, also is bag to solid
-check front bag and what you are using to hold it.REMOVE stud again. If front rest, make sure all is tight, if By-prod push forward and preload legs. My suggestion is get rid of by-pod. With Front rest use check the placement to stock. Try leaving 1.5-2" of stock protruding forward of bag.
-possible bad shoulder to stock placement.
-front scope base screw isn't in threads of barrel are they?
-torque action screws action starting with closet screw to lug and work way back to tang.
-check for barrel to stock interference.

Ok I'm out of suggestions

Give us more details
-caliber, bullets used, powder used etc...
-shooting postion
-shooting with brake, suppressed, etc...

 

[jb1023]

This is a Howa 308 w/20" #6 barrel. On targets 1 and 2, I waited 90 seconds, based on my stop watch, between shots and 2-3 minutes between strings. On target 3, I only waited 30-45 seconds between shots and about 2-3 minutes after the warm up string before firing the first string. I did feel the barrel after each shot on target 3 and it was at most luke warm.

 

[rcoody]

This is a Howa 308 w/20" #6 barrel. On targets 1 and 2, I waited 90 seconds, based on my stop watch, between shots and 2-3 minutes between strings. On target 3, I only waited 30-45 seconds between shots and about 2-3 minutes after the warm up string before firing the first string. I did feel the barrel after each shot on target 3 and it was at most luke warm.

Heat should not be the problem

Are you using a bench, rifle rest and rear bag?

Are you returning the rifle to the sane position after every Shot?

Is the rifle free to slide on the bags and rest?

Are you changing your grip between shots

I have always believed vertical is the rifle and horizontal is the shooter. That leads me to believe in this case it is not you.

Might try playing with the torque on your action screws

 

[red dawg]

needs glassed and bedded

 

[jb1023]

A couple of things to look for;

-check your rear bag. Is it solid and level, does it rock back and forth. REMOVE swivel stud, also is bag to solid
***I am using a small Holland rear bag. I have not removed the rear swivel but will do so.

-check front bag and what you are using to hold it.REMOVE stud again. If front rest, make sure all is tight, if By-prod push forward and preload legs. My suggestion is get rid of by-pod. With Front rest use check the placement to stock. Try leaving 1.5-2" of stock protruding forward of bag.
***I am using a bi-pod, Caldwell. I will remove it and use my sandbag on my next trip.

-possible bad shoulder to stock placement.
***User error is always a possibility. I was actually thinking that after the first target but felt the second 2 targets were more solid as I was concentrating on that aspect much more.

-front scope base screw isn't in threads of barrel are they?
***I will check this but the scope has been mounted for over a year.

-torque action screws action starting with closet screw to lug and work way back to tang.
***I think I am going to just torque everything again.

-check for barrel to stock interference.
***The barrel is definitely free floated.

Give us more details

-caliber, bullets used, powder used etc...
***Federal brass (2-3 loadings). Hornady 178 A-Max. IMR 4064. CCI 200 primers.
***I have some new Winchester brass but I have not prepped it yet.
***I use Lee turret press, without the indexing rod, and Lee Deluxe dies.

-shooting position
***Bench. I am on a 3" concrete top bench which sits on top of 2" square tube steel frame. The seat is just a basic metal folding chair.
-shooting with brake, suppressed, etc...
***I do not have a brake, can or anything else attached. Barrel is not even threaded, YET.

 

[jb1023]

Heat should not be the problem

Are you returning the rifle to the sane position after every Shot?
Are you changing your grip between shots?
***I am breaking position after each shot but am concentrating on my form when I get back into position.

Is the rifle free to slide on the bags and rest?
***Not sure what you mean by this. It is not in a sled or anything if that is what you mean.

Might try playing with the torque on your action screws
***Definitely on my to do list.

needs glassed and bedded

***This is also on my list. I will order the compound today.

 

[rcoody]

Are you returning the rifle to the sane position after every Shot?
Are you changing your grip between shots?
***I am breaking position after each shot but am concentrating on my form when I get back into position.

Is the rifle free to slide on the bags and rest?
***Not sure what you mean by this. It is not in a sled or anything if that is what you mean.

Might try playing with the torque on your action screws
***Definitely on my to do list.


***This is also on my list. I will order the compound today.

By slide I mean unobstructed on recoil

Removing sling studs is a part of that. You don't want the stock hanging up on recoil

I know you are holding that .308 tightly into your shoulder but it is still recoiling on the bags

When I said play with the torque on your action screws that is exactly what I meant. Try different torques Do a little search and you may find some advice in Internet land.

 

[jb1023]

By slide I mean unobstructed on recoil

Removing sling studs is a part of that. You don't want the stock hanging up on recoil

I know you are holding that .308 tightly into your shoulder but it is still recoiling on the bags

When I said play with the torque on your action screws that is exactly what I meant. Try different torques Do a little search and you may find some advice in Internet land.

Ahh. That being the case then I think I will remove my stock bag as well. Willing to try anything. I have it on only to raise my cheek rest but it has the laces on the underside and I do notice them interfering with my rear bag as I get into position. Maybe a bag with velco would be less intrusive?

 

[jb1023]

Where would I find various torque specs? I have a Howa action, B&C stock, Vortex Diamondback scope and don't recall rings or base off hand. Just trying to determine if I can use my 3/8 torque wrench or if I need to buy a torque screwdriver?

 

[rcoody]

Where would I find various torque specs? I have a Howa action, B&C stock, Vortex Diamondback scope and don't recall rings or base off hand. Just trying to determine if I can use my 3/8 torque wrench or if I need to buy a torque screwdriver?

Every shooter should have the Fat Wrench torque screwdriver. It is calibrated in inch/lbs. Should be used on all scope ring screws and any other screws calibrated in in/lbs

Is your stock wood or synthetic?

Is it pillar bedded or glass bedded?

I would start with 30 in/lb. Usually you will find you best accuracy with the rear screw a little less than the front. Pillar or glass bedded you can usually torque to as much as 65 in/lbs but don't try that on a regular wood stock

There are lots of.threads about it on the.Internet. See what has worked for others.

 

[couesaddict]

I went through some similar issues a couple years ago with my 300 rum. Finally I abandoned the bench and flopped in the dirt with a bipod and rear bag. My groups shrunk dramatically. Granted I had cheap bags for the bench but I definitely wasn't allowing the rifle to recoil consistently in that position. I haven't seen the issue as much with lower recoiling rounds but it's something you might want to look into. Also, have you shot over a chrono to check your Es? Could be something with that. Good luck. I'm not saying one position is more accurate than another but more that I personally am more consistent prone than off a bench with my form.