bedding or scope issue? both?

[mytwo60]

So I am getting erratic groups. Would shoot groups in the .2s, .4s, .6s .3s then 1.6" then back to .5s, .7s and then 1.2".

Most are all shooting lower but never higher and some will go to the right and a few to the left. the groups that opens up that is. So which is it? bad bedding job or bad scope?

this happens on both bipod and rest with rear bag. One of the groups shot 4 in one hole and one 1" lower. replacing the scope this week and hitting the range first.

300WM shooting at 100yds. 28" heavy bull barrel. shooting 3-5 shots every 6-8mins.

 

[Toby Bradshaw]

Lots of possibilities. Swapping the scope is a good first step. The barrel could be walking shots as it heats up or accumulates fouling. Are you using wind flags?

 

[mytwo60]

did not use wind flags but can't imagine in calm condition that it would shoot 1" or more lower.

 

[jonbearman]

What brand is the rifle? Is the barrel free floated? What do you use to remove copper from the barrel? Has anyone else fired it to see if it repeats?

 

[Toby Bradshaw]

did not use wind flags but can't imagine in calm condition that it would shoot 1" or more lower.

Just because the shot moved an inch doesn't mean that the wind was responsible for all of it. If it's a 0.5-0.75MOA rifle, the wind might only be responsible for 0.25-0.5" at 100 yards. That can happen easily with a small angle change on a "calm" day.

A 0.75MOA rifle will shoot about as many groups larger than that as smaller -- that's how aggregate accuracy works.