Hey guys, I thought this might be a good place to ask this question... I am having a huge horizontal change in POI with my AR15. I just finished the build and the thing was built with great quality stuff. It has a wilson tactical fluted 16" stainless 1/8 twist match barrel and a trijicon accupoint 1-4 TR24g with an American Defense mount.

Anyways, the two types of ammunition are Southwest Ammunition Barnes 110 hunting ammo and the Remington UMC 115 grain paper punching stuff. Basically the ammunition shoots completely different horizontally but about the same vertically. There is a 6-8" difference at 100 yards horizontally. If the barnes is zeroed then the remington shoots way to the right. And again, if the remington is zeroed then the barnes shoots 6-8 to the left.

Is this all because of barrel harmonics? Can it be that extreme? I dont think I would be so curious if it was only an inch or two, but 6-8 inches?? that seems crazy. I want to make sure nothing is going wrong here. Also, both rounds shoot decently well. Right at an inch at 100 yards.

Here is an old thread I found searching where something similar was happening.
http://snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2528470

Let me know what yall think. Thanks.

Different load, different POI, expect it, and choose one you want.

It does happen with different ammo that change is a little excessive at 100 yds so find the one your rifle likes better and stick with it.  The wind shouldn't effect the ammo that much at a 100 yds what was the wind like on that day?

Your issue is more than ammunition. Did you go/no go gauge your chamber ? Also, Wilson tech staff is where I'd start, this forum would be somewhere after my call to Wilson.

The recoil is affecting your aiming device. Tighten it down. Or maybee swap it out to see if that is the issue.

keep shooting.   I have fired several groups over the years  that are 1/4 high and have five shots spaced at 1 inch each for 5 inches wide.  Could not have done this if I had been trying     Inexplicable.  Rare freak of nature.  keep shooting and get some more data points.

Well see it has a trijicon accupoint 1-4 on it and an American Defense mount. Those shouldnt be the problem being that high of quality... Im thinking it just the way this barrel shoots these bullets. Im going to try a few different types of ammo and see what they do. thanks.

I'm going to vote different loads different barrel harmonics.  I just verified the sighted in for my Rem 700 mountain rifle in .260 Rem. a couple weeks ago.  I had 3 different loads:  Factory 140 gr. Corelokt, factory 125 gr Partitions, and handloaded 140 gr Hornady SSTs.  They all shot decent groups but to very distictly different points of aim.  The distance between the furthest two goups was about 4-5 inches at 100 yards.

I sighted in for the 125 grainers and put the target with all the labeled groups in my rifle case.  In the unlikely event I shoot the 6 remaining 125 gr. rounds while hunting I'll measure the distance between the the 125 gr. group and the group of my next ammo choice and adjust my repeatable scope.  I should then be ready to do more hunting w/o any worries about changing ammo.

Hey so here's a picture... I think my barrel hates this Barnes stuff!! Its southwest loaded ammo... no problem there at all! But I think the projectile and my barrel just don't get along. I knew I wasn't going crazy. This Barnes stuff for some reason sometimes will group and sometimes its all over the place like this picture shows. That's two nosler green tips from pnw arms that are 2 in one hole, then two umc target Remington ammo and then the Barnes all over the place but two are far left like I was saying. I went through 50 rounds of this expensive Barnes stuff trying to figure out what was going on!! Anyways, I think I'm gonna stick with green tips cause its almost the same poi as the umc target st

True.

I changed primers and it dropped 2 inches at 50 yards.