What to look for (shots stringing)?

[Acsr]

All, i have a 9 major gun that i recently changed dots on while zeroing the dot i was getting a hit at my intended area than the very next one goes high about 4 to 5 inches,  the following shoot usually prints back to the original aiming point.   This alternates, i took the gun home cleaned and inspected couldn't find a creek in the slide anywhere.   I then thought it could be the new dot so i put another dot on and the results aren't changing so it's got to be gun related so any and all help on this would be appreciated. Have pics of groups shot but can't upload.  The barrel has less than 7k on it kart barrel. 

[RangerTrace]

Are you getting hits on the comp?  Also, check some of your rounds that have chambered to make sure you aren't getting bullet setback from the feedramp.  

[xjwalt666]

Check the screws that hold the dot mount to the frame. I had the exact same issue with my sons open gun and the screws loosened up a bit and the mount was rocking. 

[Acsr]

1 hour ago, RangerTrace said:

Are you getting hits on the comp?  Also, check some of your rounds that have chambered to make sure you aren't getting bullet setback from the feedramp.  

I've checked this no comp strikes and mags are feeding into chamber. 

[Acsr]

33 minutes ago, xjwalt666 said:

Check the screws that hold the dot mount to the frame. I had the exact same issue with my sons open gun and the screws loosened up a bit and the mount was rocking. 

Dot mount and screws are secure

[shred]

Push hard on the scope mount backwards and forwards.  I've seen more than one "tight" mount move when you do that.  Also make sure the screws aren't dragging the slide either from the top or side.

 

Throwing the first shot out of a group is not uncommon for some pistols when hand-cycled.

 

 

[Acsr]

The problem is it keeps alternating first shot on target next shot high, next shot back to intended aiming point. 

[xjwalt666]

12 hours ago, Acsr said:

The problem is it keeps alternating first shot on target next shot high, next shot back to intended aiming point. 

That’s exactly what was happening when the mount loosened up. But if it’s all tight then obviously not the issue

[shred]

13 hours ago, Acsr said:

The problem is it keeps alternating first shot on target next shot high, next shot back to intended aiming point. 

That sure sounds like something is loose.  Could be in the barrel link area, but I'd still double-check everything in the dot mount first.  I had one LO mount where the screws were too long and they were nice and tight but the dot itself still had some play in it.

 

[Acsr]

14 minutes ago, shred said:

That sure sounds like something is loose.  Could be in the barrel link area, but I'd still double-check everything in the dot mount first.  I had one LO mount where the screws were too long and they were nice and tight but the dot itself still had some play in it.

 

I'll recheck again

[DavidSeavey]

that's what my czechmate did when the mount loosened up the first time, windage was fine but it spread way out vertically. 

[CHA-LEE]

If the scope mount is solidly mounted but the vertical stringing continues you can try putting a much heavier recoil spring in the gun to see if that changes the stringing behavior. A heavier recoil spring will help reproduce a consistent lockup position of the barrel every time the slide cycles. If a heavier recoil spring eliminates or improves the vertical stringing issue then the root cause of the issue could be many different things such as poor barrel lock up fit, worn slide stop pin, and or slide to frame fit. Frame mounted red dots expose barrel/slide fit or lockup consistency issues. These issues get exposed easier the lighter the recoil spring is. For example, I am using a 7lb Recoil spring in my Open gun and EVERYTHING needs to be fitted properly and locking up consistently for that light of a recoil spring to maintain good accuracy.

[maur]

I know you said you weren't getting comp hits, but to be sure you also don't have major carbon buildup in your comp or muzzle right? That's a common issue once youre a certain numbers of rounds in, especially if youre shooting coated or similar bullets.

[jim vaughan]

Although this is an expensive option, consider having a chamber reamer and comp alignment reamer in your tool kit.

They are great to check and clean your chamber and comp.