Slack groups

[Tireur]

Hi,

Can anybody please advise as to a possible cause of the following.

I've been regularly shooting sub moa groups with my .308.

However today the group at 600yds was about 36". It went 12" high, left, right, low and then went 24" low!

I tried some factory ammo and the group really tightened up to about 1 moa.

All the variables were constant, I'm just at a loss to explain.

 

[StephenPerry]

Tireur
I'm not the best one to answer this but if I answer others will follow. Being your first Thread you will get an eyeful after I Post. Like me seeing your new baby first. Welcome aboard.
Stephen Perry

 

[jb1000br]

I guess since you went back to factory ammo without changing anything, and it did well, that rules out scope/mount issues...

Any chance you loaded the wrong powder?

Can't imaging even that would go from 1 moa to 6 MOA with just the wrong powder!

JB

 

[BarryL]

I think I would be tempted to look at the bullet.