Extreme vertical string

[Letmwork]

Hey new guy first post. I have 6.5 G that throws every third or so round 4 moa low. I am shooting 120 gr hornady and nosler. Its an AR and i am noticing that my ejection pattern is erratic some to the 1 o'clock and some to the 4 o'clock. Any ideas?

[A5BLASTER]

Factory or handloads?

Need more details before we can even try to help you.

Who's barrel? Who's bolt? Gas length? Standard or adjustable gas? What buffer weight and spring? Home build or store bought rifle?

My first guess is very inconsistent loads some having more juice then others. But we need specs to give better answers.

[Letmwork]

reloads that i did myself 120 Nosler BT 31.5 BLC2 hornadt brass. Factory hornady did the same thing, windage has been great stays good left to right 20" barrel rifle length gas system non adjuatable. Brownells bolt carrier group. Its like it falls on its face, either gas issue or maybe shooting off bags with a long freefloat hand guard is just to soft of a rest.

[CaptnC]

I did a little digging into the "fliers". I ran into a couple threads they said to trust up the upper receiver where it meets the barrel. I just received mine over the weekend. So far I've done two...getting them ready for a range trip this week and hog hunt this weekend. Both are brand new builds so I don't have any before and aftet, but I should not experience any fliers.

I will have the chronograph monitoring the shots, so any velocity fliers should be spotted right away.

I went cheap, because the were sold out of the most recommended brand, so I settled for the Wheeler brand.

[LR1955]

Hey new guy first post. I have 6.5 G that throws every third or so round 4 moa low. I am shooting 120 gr hornady and nosler. Its an AR and i am noticing that my ejection pattern is erratic some to the 1 o'clock and some to the 4 o'clock. Any ideas?

Since rifles can't count so don't know when to put a shot low or high, why are you sure it wasn't you?

Here is how to check. Fire two shots then hold four inches high for two shots. If you are correct that your rifle is putting one low every three or four shots, then one of the two you deliberately shot high will be with your first two shots.

Repeat four or five times and if it happens every time, you have a problem with how your barrel was installed.

LR55

[Letmwork]

I took my gas block off to make sure it is aligned. Which it was, i am thinking i may reload slower powders and see how they perform. Could be the optic too. One thing at a time i guess.

[Glockpride]

Have you made sure your base and rings/mount on the optic are torqued down properly?

[Letmwork]

Have you made sure your base and rings/mount on the optic are torqued down properly?

First thing i did was check torques on the rifle

[A5BLASTER]

What LR55 said plus. Did you mix and match primers?

Also are you 100% sure you didn't mess up your power charge?

Did you clean the lube off the cases after resizing?

I would try LR55 test first, then go from there.

Edit to add.

Did you measure distance to lands? Are you 100% sure you seated all the bullets correctly and didn't leave some long and they are jamming?

[Klem]

Letmework,

Sounds like the majority are jamming in the lands and every fourth one (on average) is not.

Those rounds that come in contact with the lands will pressure spike and give you the 1 O'Clock ejection. The ocassional one that does not will eject normally at 4 O'Clock.

The reason why this might be the case is when bullets are not held with enough neck tension in an auto-loader. In auto feeding, rounds get slammed into the chamber and come to a violent stop. This causes the bullet to want to keep going and if the neck is not holding it firmly will carry forward into the lands (by inertia). This can also happen when the first round gets hand cranked into the chamber followed by all the rest being more violently loaded. The bullets will shift more or less.

The high rounds would be the spiked pressure in the lands and the low rounds are not jammed into the lands. A 4-MOA vertical difference in groups is about right for this scenario (it happened to me a while back).

[Letmwork]

Letmework,

Sounds like the majority are jamming in the lands and every fourth one (on average) is not.

Those rounds that come in contact with the lands will pressure spike and give you the 1 O'Clock ejection. The ocassional one that does not will eject normally at 4 O'Clock.

The reason why this might be the case is when bullets are not held with enough neck tension in an auto-loader. In auto feeding, rounds get slammed into the chamber and come to a violent stop. This causes the bullet to want to keep going and if the neck is not holding it firmly will carry forward into the lands (by inertia). This can also happen when the first round gets hand cranked into the chamber followed by all the rest being more violently loaded. The bullets will shift more or less.

The high rounds would be the spiked pressure in the lands and the low rounds are not jammed into the lands. A 4-MOA vertical difference in groups is about right for this scenario (it happened to me a while back).

I will cycle some and see if they grow, that should confirm or eliminate if thats the problem. Thanks for the insight didnt think about that.

[Letmwork]

Shot some more rounds today, the casings that go to the 1 o'clock are the ones that hit 4 moa low and they dont kick out very far. The other rounds hit where they should.

[LR1955]

Shot some more rounds today, the casings that go to the 1 o'clock are the ones that hit 4 moa low and they dont kick out very far. The other rounds hit where they should.

LW:

Got to admit I never heard of a correlation between where the brass went and the shot.

Guess you didn't try my recommendation. That would prove beyond a doubt if it were you or the rifle.

Four minutes is a lot and is not due to the powder, primers, brass, bullet, or load. Four minutes is either you or how the barrel is installed.

LR55

[Letmwork]

LW:

Got to admit I never heard of a correlation between where the brass went and the shot.

Guess you didn't try my recommendation. That would prove beyond a doubt if it were you or the rifle.

Four minutes is a lot and is not due to the powder, primers, brass, bullet, or load. Four minutes is either you or how the barrel is installed.

LR55

No i tried, problem is that it is not always the the same shot that goes low. I shot five at a time 1st and second are good then it is typically the 3rd or 4th that will drop 4 moa. And it is always 4 moa the 5th sometimes will be back to poa somethimes not. I know you dont know me or my shooting so its hard to judge via internet what the issue is. However, i am not new to ARs (18th year in the Army combat arms) or shooting and i am honest with myself when i am the problem. I do however suspect that you correct with the barrel installation so appriciate your insight. My thoery is that when they installed it didnt get torqued right and after the first few shot it heats up and shifts. Cause low impact and mis aligment in the chamber creating a pressure spike. We'll see ill report back. Thanks again for input LR55 it is giving me a place to look that i may not have.

[Letmwork]

Barrel was not properly installed, re moved and retourqed. Consistant ejection at 3:30ish and same poi
Thanks for leading me to it LR55...