[Swamprabbit]

In shooting my new CMP SG SA, I am getting quite a bit of vertical stringing of my groups. I have some range factors (varying ligt conditions being the worse) that I will eliminate in a session this weekend. I have also tightened up the front sight by "peening" (sp?) the barrel grooves and checked for clearance between the rear handguard and the receiver. Anything else I need to check that may be causing this?

 

[Cornbread2]

Make sure your gas cylinder is not putting pressure your upper handguard.

Remove your lower handguard and place the rifle back into the stock and lock your trigger group in.

Look to make sure the stock is not touching the barrel from chamber area all the way to the end of the stock.

Lower band of the barrel is the only part of the barrel that can touch the stock.

If it contacts the barrel anywhere in this area this will cause problems. With the lower handguard off you can clearly see if you are touching and if so remove some wood.

Replace your lower handguard and see it it contacts the stock. If so correct this.

Also Garands and M1a rifles will start to shoot low when they get really hot. This is caused by the heat mirage coming off the barrel affecting how you see the target because the sights are so low on the barrel.

This is something that does not happen on your AR.

 

[Cornbread2]

Also remove the rifle from the stock and check the fit of the lower handguard on the barrel.

It should float and not touch the barrel.

 

[delloro]

see if the upper handguarrd is loose when cold and tight when hot. it can be that simple.

 

[Relay4]

Maybe the problem lies with the shooter. Vertical stringing can also be the result of a lack of breath control.

 

[30Cal]

Rear sight tension.

 

[Swamprabbit]

Maybe the problem lies with the shooter. Vertical stringing can also be the result of a lack of breath control.

I was just waiting for that one to come out.

 

[Cornbread2]

I don't think it is the shooter.

He is not a sandbagger. He shoots expert or master class highpower scores.

 

[janitorjim]

What's vertical stringing?

 

[Jacobite]

What's vertical stringing?

It is when your groups start to form a line up and down but stay consistant right to left. Vey common in rifles with a bedding problem or in black powder guns when they get fouled badly.

 

[jocko]

Maybe- the gas plug is loose?