Different loads shift POI left/right

[ken226]

3 different .260 loads all with the same bullet (140 Amax), Same OAL (2.82),, same primers, but different powder charges.

42.0 grains of H4350, zeroed
42.4 grains of AA4350, 4.5 moa right of above zero. Exactly to the right, no elevation change.
43.2 grains of AA4350, 2moa right of H4350 zero. Again, exactly to the right, no elevation change.

So basically, the H4350 load shoots really tight, 1/2 inch groups dead center. The 42.4 AA4350 load shoots tight as well, about .6in groups but 4.5 in right of center. The 43.2 grain AA4350 load shoots about .75 in groups, but about 2 inches right of center.

Is this normal?

 

[M14 Shooter]

I have seen different powders shift point of impact left or right.For example when I was shooting my Ar-15 .The load with AA2520 would shoot 3 minutes to right compared to
Reloader -15 Loads with the same bullet 77SMK.

Regards Mike

 

[sib1948]

I've seen the same thing with different loads and powders. As long as each load is consistently off you should be good. Just have to adjust your zero, depending on what you're shooting.

 

[MitchAlsup]

Yep, normal.

Different loadings cause the barrel to vibrate in different ways. The direction of the barrel when the bullet leaves the muzzle is critical.

 

[witchhunter]

yup, shoot groups, not worrying about POI until you are done with the work up loads. Then adjust your POI to where you want it. Done.

 

[BuzzBoss915]

I would say normal, but excessive. First of all, stick with the H4350 unless you have a good reason. Then, if you have a reason, or you ran out of H4350, zero for the other powder and don't worry about it. Apparently the harmonics are just "different"? You should expect a slight shift of POI when you change any component, but what you are getting seems beyond normal, way beyond. Assuming the accuracy is comparable? Yes/no? BB