Linear group: What can tighten this group up? - Page 2

Picher · May 9, 2018, 01:53 PM

Shooting off a bipod is often not as precise as off a good front benchrest setup and rear bag. Other considerations are whether you are very consistent with shoulder contact, grip, and trigger squeeze.

Do you have wind flags in various distances from bench to target? Watch flags and shoot with a consistent condition. If the condition changes, shoot a sighter or two to determine a new aiming point or sight setting that keeps the next record round in the group.

With regard to the rifle, have you adjusted the action screws to a certain torque that shoots better than just a haphazard setting? That takes some testing.

Someone else mentioned parallax or objective setting.

Txhillbilly · May 11, 2018, 03:44 PM

TXAZ, Quit shooting Boomer before you shoot this one. That's your problem!

More than likely it is a combination of trigger, rest, and the shooter.

Rimfire5 · May 13, 2018, 10:42 AM

TXAZ,

Just a thought on another cause of the linear spread.
In addition to the possibility of wind gusts, I have noticed that with a solid front rest and rear bag, that I can cause the POI to move right if I do not have my stock set exactly on my shoulder. One indicator is that when the rifle recoils the scope is not on the aim point when the rifle finishes from the recoil.

When I have the stock set right, the scope come back to the POA. When it is off the correct spot, the scope comes back to the right of the POA and the POI is to the right, just about the same distance to where your right most three shots are.

TXAZ · May 13, 2018, 12:21 PM

Quote:

Originally Posted by Txhillbilly

TXAZ, Quit shooting Boomer before you shoot this one. That's your problem!

More than likely it is a combination of trigger, rest, and the shooter.

Actually I hadn’t shot Boomer since we met at the GTG.
I’m thinking it was trigger finger position.
The front bipod is a rock solid Atlas and the back bag was reasonably solid.

Picher · May 24, 2018, 01:16 PM

There's another factor that people either don't know about, or forget. That is water vapor that causes the target to appear in a different position than it really is, either higher or to one side.

I can't say that I'm an expert, but have noticed horizontal or diagonal stringing when there is almost no wind, especially in the morning, or after a rain.

Since it can't be seen the only way to check is to set up a survey transit to monitor the apparent movement of the target. If you set your rifle on the bags and not touch it, sometimes you can note that the target appears to move sideways or diagonally on an angle when there's little wind.

Scorch · May 24, 2018, 02:59 PM

Horizontal string is always a bedding issue.

DPI7800 · May 24, 2018, 04:47 PM

TXAZ, what rifle, barrel and scope? When the scope was mounted was it mounted to you or for the person who put it on.

I ask because the horizontal stinging can also be a result of not having proper eye relief. Also is the comb height set properly? Do find you are fighting to get consistent cheek compression or is it spot on shot to shot?

Picher · June 15, 2018, 11:16 AM

I like to hold the forend down on the front sandbag to keep the rifle from moving at the shot. Just be careful to hold straight down and not more on one side. Also make sure that, if using an adjustable front rest, that it's tightened down well.

Check to assure that you're looking through the scope perfectly aligned each time. If your eye is the right distance from the eyepiece, the image will fit perfectly in the eyepiece. If too close to it, you won't be able to assure that parallax isn't present. Some manufacturers set parallax for 150 yards, so you have to be sure to center the image to prevent elongated groups cause by parallax errors.

velocette · June 15, 2018, 01:10 PM

Horizontal stringing can often be caused by not being squarely behind the rifle.
This is more common when shooting from a bench with a rest but can also be found when shooting prone with a rest.
When one is not squarely behind the rifle the recoil can push the rifle to the side.

May 24, 2018, 02:59 PM	#31
Scorch Senior Member Join Date: February 13, 2006 Location: Washington state Posts: 15,248	Horizontal string is always a bedding issue. __________________ Never try to educate someone who resists knowledge at all costs. But what do I know? Summit Arms Services

June 15, 2018, 01:10 PM	#34
velocette Senior Member Join Date: May 25, 2007 Location: South Florida Posts: 924	Horizontal stringing can often be caused by not being squarely behind the rifle. This is more common when shooting from a bench with a rest but can also be found when shooting prone with a rest. When one is not squarely behind the rifle the recoil can push the rifle to the side. __________________ Trigger control + Breath control + Sight alignment = Gun Control. http://www.hrpclub.info/ NRA Smallbore Prone Master, High Power Master

May 9, 2018, 01:53 PM	#26
Picher Senior Member Join Date: December 14, 2004 Location: Maine Posts: 3,694	Shooting off a bipod is often not as precise as off a good front benchrest setup and rear bag. Other considerations are whether you are very consistent with shoulder contact, grip, and trigger squeeze. Do you have wind flags in various distances from bench to target? Watch flags and shoot with a consistent condition. If the condition changes, shoot a sighter or two to determine a new aiming point or sight setting that keeps the next record round in the group. With regard to the rifle, have you adjusted the action screws to a certain torque that shoots better than just a haphazard setting? That takes some testing. Someone else mentioned parallax or objective setting.

May 11, 2018, 03:44 PM	#27
Txhillbilly Senior Member Join Date: July 5, 2008 Posts: 512	TXAZ, Quit shooting Boomer before you shoot this one. That's your problem! More than likely it is a combination of trigger, rest, and the shooter.

May 13, 2018, 10:42 AM	#28
Rimfire5 Senior Member Join Date: January 2, 2009 Location: Northern Virginia Posts: 922	TXAZ, Just a thought on another cause of the linear spread. In addition to the possibility of wind gusts, I have noticed that with a solid front rest and rear bag, that I can cause the POI to move right if I do not have my stock set exactly on my shoulder. One indicator is that when the rifle recoils the scope is not on the aim point when the rifle finishes from the recoil. When I have the stock set right, the scope come back to the POA. When it is off the correct spot, the scope comes back to the right of the POA and the POI is to the right, just about the same distance to where your right most three shots are.

May 24, 2018, 01:16 PM	#30
Picher Senior Member Join Date: December 14, 2004 Location: Maine Posts: 3,694	There's another factor that people either don't know about, or forget. That is water vapor that causes the target to appear in a different position than it really is, either higher or to one side. I can't say that I'm an expert, but have noticed horizontal or diagonal stringing when there is almost no wind, especially in the morning, or after a rain. Since it can't be seen the only way to check is to set up a survey transit to monitor the apparent movement of the target. If you set your rifle on the bags and not touch it, sometimes you can note that the target appears to move sideways or diagonally on an angle when there's little wind.

May 24, 2018, 04:47 PM	#32
DPI7800 Senior Member Join Date: July 15, 2014 Posts: 208	TXAZ, what rifle, barrel and scope? When the scope was mounted was it mounted to you or for the person who put it on. I ask because the horizontal stinging can also be a result of not having proper eye relief. Also is the comb height set properly? Do find you are fighting to get consistent cheek compression or is it spot on shot to shot?

June 15, 2018, 11:16 AM	#33
Picher Senior Member Join Date: December 14, 2004 Location: Maine Posts: 3,694	I like to hold the forend down on the front sandbag to keep the rifle from moving at the shot. Just be careful to hold straight down and not more on one side. Also make sure that, if using an adjustable front rest, that it's tightened down well. Check to assure that you're looking through the scope perfectly aligned each time. If your eye is the right distance from the eyepiece, the image will fit perfectly in the eyepiece. If too close to it, you won't be able to assure that parallax isn't present. Some manufacturers set parallax for 150 yards, so you have to be sure to center the image to prevent elongated groups cause by parallax errors.