Range Report Huge Horizontal change in POI?? Help!

[BadBowtie03]

Hey guys, I made a post earlier today about my 300 blackout in a different forum here on the hide, but I figured this would be a better place to talk about it and I might get more help/more insight...

Basically 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 extremem? 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.

 

[LawnMM]

Re: Huge Horizontal change in POI?? Help!

Sounds mechanical if that extreme at only 100 yards. Check/Tighten down your optics mounts. Barrel nut torqued properly? Barrel free floating? How consistent is your cheek weld? Try a third type of ammunition and see which of the current two it shoots close to, thus isolating one as being "off" the baseline

 

[usmc02xx]

Re: Huge Horizontal change in POI?? Help!

that is a pretty big shift for a small weight change. what gets me is that you say its repeatable back and forth. that makes mechanical hard to swallow for me and tends to lean towards it being legit. I know that if im not in the sweet spot (ocw) for my barrel i can see big shifts in POI (3-4 inches at 100). But still, that is pretty damn big.

 

[Guest]

Re: Huge Horizontal change in POI?? Help!

Two different projectile from two different manufactures.

Most likely the baring surface difference from the different projectiles has something to do with it. Also the pressure difference might help the shift even more with the two different projectiles.

This is the same for 308 that I have shot. The 168 Barnes projectile shoot horizontal compared to the 168 matchkings. Not as much as a difference because I load them myself with the same powder but it is different.

Zach

 

[BadBowtie03]

Re: Huge Horizontal change in POI?? Help!

Thanks for the replies guys. I posted this other places and I'm getting various answers. I even called Wilson and one of their guys seemed stumped.

Hey Zach, do you think it would be possible for me to buy a couple boxes of assorted 300 blk ammo from yall to help with me figuring it out? Like if one box had two different types? So then I could buy two boxes and have four kinds of ammo? I could use large targets and see the different poi's... i want to see if I have a wild child with just one of these, and if most ammo is about the same. Does that make sense? I just feel most ammo is vertically different and not horizontally. Let me know thanks.

 

[BadBowtie03]

Re: Huge Horizontal change in POI?? Help!

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 stuff. Can yall load green tips Chris?