AR Positional POI Shift Test

[LRRPF52]

Here’s the shooting footage from the above targets

Skip to 7 minutes for the shooting

For the BCM/Geissele, the only thing I can think of for that insane deviation with the bipod prone shoot was contact with the gas block with maybe the bipod mount back-end hardware. Because it went right back to close POA=POI for the tripod-supported.

Excellent video to illustrate what we’re talking about with positional POI shift though.

 

[LRRPF52]

The rifle that has me the most curious is the Hk G28, because it uses a steel upper. Would be interesting to see if it holds more true than all the aluminum uppers.

 

[Veracity]

@Veracity you're mentioned in the SOLGW article on their new L89A handguard. Have you been able to test that + a broadsword upper for shift? I can't imagine it's much different than a traditional AR.

It's not much different. Right at .25 mil in my testing of 2 rifles. 1 is 18" and 1 is a 20". Both suppressed

 

[itsallbacon]

For the BCM/Geissele, the only thing I can think of for that insane deviation with the bipod prone shoot was contact with the gas block with maybe the bipod mount back-end hardware. Because it went right back to close POA=POI for the tripod-supported.

Excellent video to illustrate what we’re talking about with positional POI shift though.

I bet you’re right. I’m going to have to try it again.

 

[Carlos0311B4]

I wasn't aware of that. I will have to search for it and check it out. That is interesting info.

2:23

 

[lennyo3034]

Tested 3 different bullets out of new barrel today and decided to try this test. Top row is prone, bottom is barricade. Unfortunately not corresponding bullets so I labeled the groups to better match.

Mega bullet upper and KAC URX4. I know other people have posted issues with URX4 in this thread but this is my second and I haven’t had issues. I actually have a spare MML upper available but chose the URX4 on standard upper because I can get a lower height over bore with URX4.

I will note on this particular rifle I bridged the upper and handguard with the scope mount. Not intentionally, I just didn’t have a cantilever available and this was unused.

 

[Ernest 5.56]

Tested 3 different bullets out of new barrel today and decided to try this test. Top row is prone, bottom is barricade. Unfortunately not corresponding bullets so I labeled the groups to better match.
View attachment 8674148


Mega bullet upper and KAC URX4. I know other people have posted issues with URX4 in this thread but this is my second and I haven’t had issues. I actually have a spare MML upper available but chose the URX4 on standard upper because I can get a lower height over bore with URX4.

I will note on this particular rifle I bridged the upper and handguard with the scope mount. Not intentionally, I just didn’t have a cantilever available and this was unused.

View attachment 8674149

What barrel ?

 

[lennyo3034]

Bartlien either from Craddock or WOP. Been lying around for years and decided to do something with it.

 

[black5.3]

Im kinda battling with this issue right now and im leaning toward it being a fundamentals-consistency issue while shooting my rig from prone with bipod far forward and rear bag. All my groups are around 1”-1.25” and in that group I will have 3-4 rounds stacked in a .5”-.6” group and then a couple shots that blow the group out to a inch or a little more…

Rifle is a vltor Mur upper receiver, PVA Osprey 6 arc barrel, Geissele mk18 rail(bipod attached via arca on the rail), suppressed with TBAC Ultra 7 .264.

I admit I don’t have nearly as much time trying to shoot ar’s at a level of precision like i do my bolt guns and thats why im thinking its definitely me and not the gun or load(i am handloading for this gun). Barrel has right at 200 rounds on it so it should be broke in.

This is not always how it shoots but is kind of representative of how i can lay down some great groups and then the next is over an inch. Those smaller dots are right at 3/4”, the grid paper im shooting on is a weird scale.